Insert sensing system with medial-lateral shims and method therefor

ABSTRACT

An orthopedic system to monitor a parameter related to the muscular-skeletal system is disclosed. The orthopedic system includes electronic circuitry, at least one sensor, and a computer to receive measurement data in real-time. The orthopedic system comprises a first plurality of shims of a first type, a second plurality of a second type, a measurement module, and the computer. The measurement module houses the electronic circuitry and at least one sensor. The measurement module is adapted to be used with the first plurality of shims and the second plurality of shims. The measurement module has a medial surface that differs from a lateral surface by shape, size, or contour.

CROSS-REFERENCE TO RELATED APPLICATIONS Field

The present invention pertains generally to measurement of physicalparameters, and particularly to, but not exclusively, medical electronicdevices for high precision sensing.

Background

The skeletal system of a mammal is subject to variations among species.Further changes can occur due to environmental factors, degradationthrough use, and aging. An orthopedic joint of the skeletal systemtypically comprises two or more bones that move in relation to oneanother. Movement is enabled by muscle tissue and tendons attached tothe skeletal system of the joint. Ligaments hold and stabilize the oneor more joint bones positionally. Cartilage is a wear surface thatprevents bone-to-bone contact, distributes load, and lowers friction.

There has been substantial growth in the repair of the human skeletalsystem. In general, orthopedic joints have evolved using informationfrom simulations, mechanical prototypes, and patient data that iscollected and used to initiate improved designs. Similarly, the toolsbeing used for orthopedic surgery have been refined over the years buthave not changed substantially. Thus, the basic procedure forreplacement of an orthopedic joint has been standardized to meet thegeneral needs of a wide distribution of the population. Although thetools, procedure, and artificial joint meet a general need, eachreplacement procedure is subject to significant variation from patientto patient. The correction of these individual variations relies on theskill of the surgeon to adapt and fit the replacement joint using theavailable tools to the specific circumstance.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features of the system are set forth with particularity in theappended claims. The embodiments herein, can be understood by referenceto the following description, taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 illustrates an orthopedic measurement system placed in a joint ofthe musculoskeletal system in accordance with an example embodiment;

FIG. 2 is an illustration of the measurement module with a first shim ofa first type and a second shim of a second type and in accordance withan example embodiment;

FIG. 3 is a top view of the first shim coupled to the measurement moduleand the second shim coupled to the measurement module in accordance withan example embodiment;

FIG. 4 is a bottom view of the first shim coupled to the measurementmodule and a bottom view of the second shim coupled to the measurementmodule in accordance with an example embodiment;

FIG. 5 is an illustration of anterior retaining features for the firstshim and the measurement module in accordance with an exampleembodiment;

FIG. 6 is an illustration of posterior retaining features for the firstshim and the measurement module in accordance with an exampleembodiment;

FIG. 7 is a bottom view of the first shim in accordance with an exampleembodiment;

FIG. 8 is an illustration of a top view of a third shim in accordancewith an example embodiment;

FIG. 9 is an illustration of a bottom view of the third shim inaccordance with an example embodiment;

FIG. 10 is a top view of the measurement module in accordance with anexample embodiment;

FIG. 11 is a bottom view of the measurement module in accordance with anexample embodiment;

FIG. 12 is an exploded view of a first support structure and a secondsupport structure of the measurement module in accordance with anexample embodiment;

FIG. 13 is an illustration of an interior of the first support structureof the measurement module in accordance with an example embodiment;

FIG. 14 is an illustration of an interior of the second supportstructure of the measurement module in accordance with an exampleembodiment;

FIG. 15 is an illustration of electronic circuitry in the measurementmodule in accordance with and example embodiment;

FIG. 16 is a bottom view of the second shim in accordance with anexample embodiment;

FIG. 17 is a block diagram of the electronic circuitry in themeasurement module in accordance with an example embodiment;

FIG. 18 is a block diagram of a measurement system or computer inaccordance with an example embodiment;

FIG. 19 is an illustration of a communication network for measurementand reporting in accordance with an exemplary embodiment;

FIG. 20 is an illustration of the orthopedic measurement systemincluding a handle and a tibial prosthetic component in accordance withan example embodiment;

FIG. 21 is an illustration of the tibial prosthetic component inaccordance with an example embodiment; and

FIG. 22 is an illustration of the insert of FIG. 2 coupled to the tibialprosthetic component in accordance with an example embodiment.

DETAILED DESCRIPTION

Embodiments of the invention are broadly directed to measurement ofphysical parameters, and more particularly, to fast-response circuitrythat supports accurate measurement of small sensor changes.

The following description of embodiment(s) is merely illustrative innature and is in no way intended to limit the invention, itsapplication, or uses.

For simplicity and clarity of the illustration(s), elements in thefigures are not necessarily to scale, are only schematic, arenon-limiting, and the same reference numbers in different figures denotethe same elements, unless stated otherwise. Additionally, descriptionsand details of well-known steps and elements are omitted for simplicityof the description. Notice that once an item is defined in one figure,it may not be discussed or further defined in the following figures.

The terms “first”, “second”, “third” and the like in the Claims or/andin the Detailed Description are used for distinguishing between similarelements and not necessarily for describing a sequence, eithertemporally, spatially, in ranking or in any other manner. It is to beunderstood that the terms so used are interchangeable under appropriatecircumstances and that the embodiments described herein are capable ofoperation in other sequences than described or illustrated herein.

Processes, techniques, apparatus, and materials as known by one ofordinary skill in the art may not be discussed in detail but areintended to be part of the enabling description where appropriate.

The orientation of the x, y, and z-axes of rectangular Cartesiancoordinates is assumed to be such that the x and y axes define a planeat a given location, and the z-axis is normal to the x-y plane. The axesof rotations about the Cartesian axes of the device are defined as yaw,pitch and roll. With the orientation of the Cartesian coordinatesdefined in this paragraph, the yaw axis of rotation is the z-axisthrough body of the device. Pitch changes the orientation of alongitudinal axis of the device. Roll is rotation about the longitudinalaxis of the device.

The orientation of the X, Y, Z axes of rectangular Cartesian coordinatesis selected to facilitate graphical display on computer screens havingthe orientation that the user will be able to relate to most easily.Therefore the image of the device moves upward on the computer displaywhenever the device itself moves upward for example away from thesurface of the earth. The same applies to movements to the left orright.

Although inertial sensors are provided as enabling examples in thedescription of embodiments, any tracking device (e.g., a GPS chip,acoustical ranging, accelerometer, magnetometer, gyroscope,inclinometers, MEMs devices) can be used within the scope of theembodiments described.

At least one embodiment is directed to a kinetic orthopedic measurementsystem to aid a surgeon in determining real time alignment, range ofmotion, loading, impingement, and contact point of orthopedic implantsunder load. Although the system is generic and can be adapted for use asa measurement device it can used as part in a trialing implant, apermanent implant, or a tool. The measurement device and can be used inthe spine, shoulder, knee, hip, ankle, wrist, finger, toe, bone, ormusculoskeletal, etc.). In a non-limiting example disclosed herein themeasurement device and system is illustrated to support the implantationof a knee joint.

The non-limiting embodiment described herein is related to quantitativemeasurement based orthopedic surgery and referred to herein as thekinetic system. The kinetic system includes a sensor system thatprovides quantitative measurement data and feedback that can be providedvisually, audibly, or haptically to a surgeon or surgical team. Thekinetic system provides the surgeon real-time dynamic data regardingforce, pressure, or loading within the musculoskeletal system, contactand congruency through a full range of motion, and information regardingimpingement.

In general, kinetics is the study of the effect of forces upon themotion of a body or system of bodies. Disclosed herein is a system forkinetic assessment of the musculoskeletal system. The kinetic system canbe for general measurement of the musculoskeletal system, trialinstallation and measurement of prosthetic components, or long-termmonitoring of an installed permanent prosthetic component to themusculoskeletal system. For example, in an installation of a trialingprosthetic component one or more bone surfaces have to be prepared toreceive a device or prosthetic component. The kinetic system is designedto take quantitative measurements of at least the load, position ofload, or alignment with the forces being applied to the joint similar tothat of a final joint installation. The kinetic system can support theactual bone cut for optimal contact point(s), balance, load magnitude,and alignment over a range of motion. The one or more measurementcomponents having sensors are designed to allow ligaments, tissue, andbone to be in place while the quantitative measurement data is taken andreported in real-time. This is significant because the bone cuts takeinto account the kinetic forces where a kinematic assessment andsubsequent bone cuts could be substantial changed from an alignment,load, and position of load once the joint is reassembled. Furthermore,the measurement data can be transmitted to a computer in the operatingroom that can analyze the measurement data and propose a workflow forthe surgical team to yield the desired results. Moreover, the kineticsystem supports real-time adjustments such as bone cuts, rotation of aprosthetic component, or ligament tensioning with real-time measurementsto validate the surgical procedure or the proposed workflow.

A prosthetic joint installation can benefit from quantitativemeasurement data in conjunction with subjective feedback of theprosthetic joint to the surgeon. The quantitative measurements can beused to determine adjustments to bone, prosthetic components, or tissueprior to final installation. Permanent sensors can also be housed infinal prosthetic components to provide periodic data related to thestatus of the implant. Data collected intra-operatively and long-termcan be used to determine parameter ranges for surgical installation andto improve future prosthetic components. The physical parameter orparameters of interest can include, but are not limited to, measurementof alignment, load, force, pressure, position, displacement, density,viscosity, pH, spurious accelerations, color, movement, particulatematter, structural integrity, and localized temperature. Often, severalmeasured parameters are used to make a quantitative assessment. Agraphical user interface can support assimilation of measurement data.Parameters can be evaluated relative to orientation, alignment,direction, displacement, or position as well as movement, rotation, oracceleration along an axis or combination of axes by wireless sensingmodules or devices positioned on or within a body, instrument,appliance, vehicle, equipment, or other physical system.

At least one embodiment is directed to a system for adjusting ormonitoring a contact position of a musculoskeletal joint for stabilitycomprising: a prosthetic component configured to rotate after beingcoupled to a bone; a sensored prosthesis having an articular surfacewhere the sensored prosthesis is configured to couple to the prostheticcomponent, where the sensored prosthesis has a plurality of load sensorscoupled to the articular surface and a position measurement systemconfigured to measure position, slope, rotation, or trajectory, and aremote system configured to wirelessly receive quantitative measurementdata from the sensored prosthesis where the remote system is configuredto display the articular surface, where the remote system is configuredto display position of applied load to the articular surface, and wherethe remote system is configured to report impingement as themusculoskeletal joint is moved through a range of motion (ROM).

While the specification concludes with claims defining the features ofthe invention that are regarded as novel, it is believed that theinvention will be better understood from a consideration of thefollowing description in conjunction with the drawing figures, in whichlike reference numerals are carried forward.

The example embodiments shown herein below of the measurement device areillustrative only and does not limit use for other parts of a body. Themeasurement device can be a tool, equipment, implant, or prosthesis thatmeasures at least one parameter or supports installation of prostheticcomponents to the musculoskeletal system. The measurement device can beused on bone, the knee, hip, ankle, spine, shoulder, hand, wrist, foot,fingers, toes, and other areas of the musculoskeletal system. Ingeneral, the principles disclosed herein are meant to be adapted for usein all locations of the musculoskeletal system.

FIG. 1 illustrates an orthopedic measurement system 100 placed in ajoint of the musculoskeletal system in accordance with an exampleembodiment. In the example, orthopedic measurement system 100 is aprosthetic component but can be a tool or device that couples to themusculoskeletal system to provide quantitative measurement data. Theprosthetic component can be a temporary installation within a prostheticjoint or a permanent installation. Quantitative measurement data fromthe prosthetic component is transmitted to a computer 110 having adisplay 112. Computer 110 can be in proximity to the prostheticcomponent to provide feedback and analysis of the quantitativemeasurement data in real-time and displayed on display 112. As shown,orthopedic measurement system 100 is used in an operating room as atrialing device that supports installation of a final prosthetic joint.The trialing device provides quantitative measurement data related toloading, balance, alignment, and motion of the joint. In one embodiment,the prosthetic component includes a plurality of sensors to generatequantitative measurement data. The prosthetic component is made similarto the final prosthetic component such that the quantitative measurementdata transfers or will be equivalent to what the final prostheticcomponent will see. A final prosthetic component can also have aplurality of sensors for providing quantitative measurement datalong-term. As shown, the orthopedic measurement system 100 is used for aprosthetic knee joint installation but can be adapted for a hip joint,ankle joint, shoulder joint, elbow, spine, knee hand, foot, wrist, otherjoints, non-joint applications related to the musculoskeletal system,bone, or orthopedic measurements.

In general, orthopedic measurement system 100 is coupled to or inproximity to the musculoskeletal system to measure a parameter. In anon-limiting example, orthopedic measurement system 100 is used tomeasure parameters that support a procedure such as an installation ofan artificial joint. Embodiments of orthopedic measurement system 100are broadly directed to measurement of physical parameters such as load,position of load, temperature, pH, alignment, position, wear, prosthesisbond strength, color, infection, or turbidity to name but a few. In-situmeasurements such as load magnitude and position of load duringorthopedic joint implant surgery would be of substantial benefit toverify an implant is in balance and under appropriate loading ortension. In one embodiment, the instrument is similar to and operateswith other instruments currently used by surgeons. Thus, the surgeonneeds minimal training on the use of the prosthetic component withsensors such that orthopedic measurement system 100 can be incorporatedinto the procedure with little or no increase in surgical time, yetyield quantitative measurement data that can be used to verifysubjective field as well as indicate if an issue is present. Moreover,this stimulates acceptance of the technology thereby reducing theadoption cycle of orthopedic measurement system 100. The surgeon caninstall prosthetic components within predetermined ranges determined byquantitative measurement data that maximizes the working life of thejoint prosthesis and reduce costly revisions based on clinical evidence.

Orthopedic measurement system 100 generates quantitative measurementdata specific for a patient installation that is also part of a largerdatabase that is used for assessment and long-term analysis and trendson prosthetic joint operation and reliability. For example, orthopedicmeasurement system 100 can be used as a trialing device to generate datain real-time to support measurement of the musculoskeletal system.Alternatively, orthopedic measurement system 100 can be used as apermanent device to monitor the patient musculoskeletal system over anextended period of time. In the example, orthopedic measurement system100 comprises a prosthetic component having one or more sensorsconfigured to provide quantitative measurement data when installed inthe musculoskeletal system. The quantitative measurement data is used tosupport optimal installation of a prosthetic joint or prostheticcomponent. A transceiver in orthopedic measurement system 100 cantransmit the measurement data to a computer 110. Computer 110 has adisplay 112 whereby the measurement results can be shown and updated aschanges are made in real-time to support installation using thequantitative measurement data. In one embodiment, computer 110 anddisplay 112 are placed in an operating room where the quantitativemeasurement data is provided to a surgeon for immediate review. Computer110 can be programmed to convert the measurement data into a visual,audible, or haptic format that supports providing the information in amanner that the surgeon can use in real-time and plan a next step basedon quantitative measurement data.

A left leg comprises a femur 102 and a tibia 104. In the example, theorthopedic system 100 supports a total or partial knee arthroplasty fora left knee or a right knee. A left total knee arthroplasty comprises afemoral prosthetic component 116 of a first type, an insert 170 of afirst type, and a tibial prosthetic component 118 of a first type. Ingeneral, the prosthetic components of the first type are specific to theleft leg, are non-symmetric, and are not suitable to be used on a rightleg. Bone cuts are required to prepare surfaces for receiving theprosthetic components. The bone cuts can also support alignment of femur102 and tibia 104 to a mechanical axis of the leg. Femoral prostheticcomponent 116 couples to a distal end of femur 102. Tibial prostheticcomponent 118 couples to a proximal end of tibia 104. An insert 170couples to and is retained by the tibial prosthetic component 118.Typically, insert 170 is placed in a tibial tray of tibial prostheticcomponent 118. Insert 170 has at least one articular surface thatcouples to a corresponding condyle of femoral prosthetic component 116to support movement of the prosthetic left knee joint. The leftprosthetic knee joint is retained by the ligaments and tendons of theleft knee.

Insert 170 for the left prosthetic knee joint comprises a shim and ameasurement module 180. The shim couples to measurement module 180 toform insert 170. A plurality of shims 124 of the first type are providedto adjust the height of insert 170. Each shim of plurality of shims 124corresponds to an insert height of a final insert or permanent insert ofthe first type that will be installed into the final knee joint afterthe correct shim height, insert rotation, range of motion, alignment,load magnitude, or position of load is identified through quantitativemeasurement. In general, after installation of femoral prostheticcomponent 116 and tibial prosthetic component 118 a shim from pluralityof shims 124 is selected. The shim selected is chosen to produce aheight on insert 170 that when inserted in the prosthetic knee jointwill place the ligaments and tendons under tension such that the kneejoint optimally loads insert 170. If insert 170 is too tight within theprosthetic knee joint (e.g. measured pressure is too high) then the shimis removed and a shim of lesser height from the plurality of shims 124is placed with measurement module 180. Re-inserting insert 170, with thelesser height shim should produce a lower pressure reading on thearticular surfaces. The process of shim replacement and reinsertinginsert 170 in the prosthetic knee joint can continue until an optimalpressure is found. In general, the surgeon makes the bone cuts for apredetermined insert height 170. In one embodiment, a pressure range canbe compared to the measured pressure applied to insert 170. For example,a red light-green light could be used on display 112 to notify thesurgeon that the pressure is within an acceptable range or out of rangethereby requiring a change of shim. The left prosthetic knee joint couldbe difficult to move through a range of motion under high loading. Ifinsert 170 measures a low pressure within the prosthetic knee joint(e.g. too loose) the shim is removed and a shim from the plurality ofshims 124 having an increased height replaces the previous shim.Re-inserting insert 170 in the prosthetic knee with different shims cancontinue until an optimal pressure is found.

In the example, plurality of shims 124 comprises 7 shims each having adifferent height. In one embodiment, plurality of shims 124 comprisesshims 130, 132, 134, 136, 138, 140, and 142 respectively having a heightwith module 180 attached of 10, 11, 12, 13, 14, 16, and 18 millimeters.There will also be a corresponding set of final inserts of 10, 11, 12,13, 14, 16, and 18 millimeters that will replace insert 170 in the jointwhen an optimal insert height has been selected. As mentionedpreviously, plurality of shims 124 are of a first type that can be usedfor a left prosthetic knee joint. Each shim of plurality of shims 124 isnon-symmetrical. In one embodiment, each shim of plurality of shims 124is non-symmetrical about an anterior-posterior axis. Each shim of theplurality of shims 124 has a medial articular surface and a lateralarticular surface to support movement of the left prosthetic knee joint.In one embodiment, the medial articular surface differs from the lateralarticular surface in area, contour, or shape on each shim of pluralityof shims 124.

Measurement module 180 includes one or more sensors to measure one ormore parameters of the musculoskeletal system. Parameters that can bemeasured by measurement module 180 can include force, pressure, load,position of load, tension, shear, relative position, acceleration,velocity, absolute position, temperature, pH, bone density, fluidviscosity, temperature, strain, angular deformity, vibration, venousflow, lymphatic flow, load, torque, distance, tilt, rotation, shape,elasticity, motion, bearing wear, subsidence, bone integration, changein viscosity, turbidity, kinematics, stability, or vascular flow.Measurement module 180 further includes a tracking system that canmeasure position, rotation, and slope. In one embodiment, the trackingsystem comprises inertial sensors, accelerometers, a GPS chip,acoustical ranging, magnetometers, gyroscopes, inclinometers, or MEMssensors that measure up to 9 degrees of freedom. Data collectedintra-operatively and long term can be used to determine parameterranges for surgical installation and to improve future prostheticcomponents. Parameters can be evaluated relative to orientation,alignment, direction, displacement, or position as well as movement,rotation, or acceleration along an axis or combination of axes bywireless sensing modules or devices positioned on or within a body,instrument, appliance, vehicle, equipment, or other physical system.

Measurement module 180 couples to a selected shim of plurality of shims124 to form insert 170. Measurement module 180 has a first side 194 anda second side 196. The first side 194 of measurement module 180comprises a medial surface 182 and a lateral surface 184. The medialsurface 182 of measurement module 180 differs in area, contour, or shapefrom the lateral surface 184 of measurement module 180. In oneembodiment, medial surface 182 and lateral surface 184 isnon-symmetrical about the anterior-posterior axis. The medial surface182 and the lateral surface 184 respectively couples to the medialarticular surface and the lateral articular surface of the selected shimof plurality of shims 124. In one embodiment, measurement module 180includes a first plurality of load sensors underlying medial surface 182and a second plurality of load sensors underlying lateral surface 184 ofmeasurement module 180. Loading applied to the medial articular surfaceand the lateral articular surface of the selected shim of the first typerespectively loads medial surface 182 and lateral surface 184 ofmeasurement module 180. Electronic circuitry in measurement module 180couples to the first and second plurality of load sensors. Theelectronic circuitry is configured to support a measurement process andtransmit measurement data. In one embodiment, the first plurality ofload sensors couples between the medial surface 182 on the first side194 of measurement module 180 and the medial surface 186 on the secondside 196 of measurement module 180. Similarly, the second plurality ofload sensors couples between the lateral surface 184 on the first side194 of measurement module 180 and the lateral surface 188 on the secondside 196 of the measurement module 180. In the example, measurementmodule 180 is configured to receive a compressive loading by themusculoskeletal system.

Orthopedic measurement system 100 further supports installation of aright prosthetic knee joint. A right leg comprises a femur 106 and atibia 108. In the example, the orthopedic system 100 can support a totalright knee arthroplasty or a partial knee joint repair. A right totalknee arthroplasty comprises a femoral prosthetic component 120 of asecond type, an insert 172 of a second type, and a tibial prostheticcomponent 122 of a second type. In general, the prosthetic components ofthe second type are specific to the right leg and are not suitable to beused on a left leg. Bone cuts are required to prepare surfaces forreceiving the prosthetic components. The bone cuts can also supportalignment of femur 106 and tibia 108 to a mechanical axis of the leg.Femoral prosthetic component 120 couples to a distal end of femur 106.Tibial prosthetic component 122 couples to a proximal end of tibia 108.Insert 172 couples to and is retained by tibial prosthetic component122. Typically, insert 172 is placed in a tibial tray of tibialprosthetic component 122. Insert 172 has at least one articular surfacethat couples to a corresponding condyle of femoral prosthetic component120 to support movement of the prosthetic right knee joint. The rightprosthetic knee joint is retained by the ligaments and tendons of theright knee thereby applying a compressive force on insert 172.

Insert 172 for the right prosthetic knee joint comprises a selected shimof plurality of shims 126 of the second type and measurement module 180.The selected shim of the second type couples to measurement module 180to form insert 170. In one embodiment, second side 196 of measurementmodule 180 couples to the selected shim of plurality of shims 126. Thesecond side 196 of measurement module 180 has a medial surface 186 and alateral surface 188 that respectively couples to the medial articularsurface and the lateral articular surface of the selected shim ofplurality of shims 126 of the second type. In one embodiment, the secondside 196 of measurement module 180 is non-symmetrical about theanterior-posterior axis. The medial surface 186 differs from lateralsurface 188 in area, contour, or shape. Thus, the first side 194 ofmeasurement module couples to the selected shim of the first type of theplurality of shims 124 and the second side 196 of measurement module 180couples to the selected shim of the second type of the plurality ofshims 126. The plurality of shims 126 of the second type are provided toadjust the height of insert 172. Each shim of plurality of shims 126corresponds to an insert height of a final insert or permanent insert ofthe second type that will be installed after the correct shim height,insert rotation, range of motion, alignment, load magnitude, or positionof load is identified through quantitative measurement. In general,after installation of femoral prosthetic component 120 and tibialprosthetic component 122 a shim from plurality of shims 126 is selected.The selected shim is chosen to produce a height on insert 172 that wheninserted in the right prosthetic knee joint will result in the ligamentsand tendons of the knee joint optimally loading insert 172 of the secondtype. If insert 172 is too tight within the prosthetic knee joint (e.g.measured pressure is too high) then the shim is removed and a shim fromthe plurality of shims 126 having a lesser height replaces the previousshim. Re-inserting insert 170 with the shim of lesser height shouldproduce a lower pressure reading and also support freer movement of theright knee joint. The process of shim replacement and reinserting insert172 in the prosthetic right knee joint can continue until an optimalpressure is found. In one embodiment, a known optimal pressure range canbe compared to the measured pressure applied to insert 172. For example,a red light-green light could be used on display 112 to notify thesurgeon that the pressure is within an acceptable range or out of rangethereby requiring a change of shim. Orthopedic measurement system 100can further produce a workflow to select a shim or make an adjustmentbased on the measurement data. If insert 172 measures a low pressurewithin the prosthetic knee joint (e.g. too loose) the selected shim isremoved and a shim from the plurality of shims 126 having an increasedheight replaces the previously selected shim. Re-inserting insert 172 inthe prosthetic knee with different shims of increased height cancontinue until an optimal pressure is found.

In the example, plurality of shims 126 comprises 7 shims each having adifferent height. In one embodiment, plurality of shims 126 comprisesshims 150, 152, 154, 156, 158, 160, and 162 respectively having a heightwith module 180 attached of 10, 11, 12, 13, 14, 16, and 18 millimeters.There will also be a corresponding set of final inserts or permanentinserts of 10, 11, 12, 13, 14, 16, and 18 millimeters that will replaceinsert 172 in the right knee joint when an optimal insert height hasbeen selected. The measurements from shims 126 and module 180 shouldcorrespond to what is seen on the final inserts. As mentionedpreviously, plurality of shims 126 are of the second type that can beused for a prosthetic right knee joint. Each shim of plurality of shims126 is non-symmetrical. In one embodiment, each shim of plurality ofshims 126 is non-symmetrical about an anterior-posterior axis. Each shimof the plurality of shims 126 has a medial articular surface and alateral articular surface to support movement of the prosthetic rightknee joint. In one embodiment, the medial articular surface differs fromthe lateral articular surface in area, contour, or shape on each shim ofplurality of shims 126.

In general, orthopedic measurement system comprises plurality of shims124 of the first type, plurality of shims 126 of the second type,measurement module 180, and a computer 112. Shims of the first type areconfigured for use in a prosthetic left knee joint and cannot be used ina prosthetic right knee joint. Similarly, shims of the second type areconfigured for use in a prosthetic right knee joint and cannot be usedin a prosthetic left knee joint. Plurality of shims 126 each have amedial articular surface and a lateral articular surface that arenon-symmetrical about the anterior-posterior axis. Plurality of shims126 each have a medial articular surface and a lateral articular surfacethat are non-symmetrical about the anterior posterior axis. In oneembodiment, the medial articular surface of each shim of plurality ofshims 126 differs from the lateral articular surface by area, contour,or shape. Measurement module 180 has medial surface 182 and lateralsurface 184 on first side 194. Similarly, measurement module 180 hasmedial surface 186 and lateral surface 188 on second side 196. In oneembodiment measurement module 180 is configured to measure loadingapplied to one of the plurality of shims 124 or one of the plurality ofshims 126 when installed respectively in a prosthetic left knee joint ora prosthetic right knee joint. First side 194 of measurement module 180is configured to couple to one of plurality of shims 124 when forminginsert 170. Second side 196 is configured to couple to one of pluralityof shims 126 to when forming when forming insert 172. The use of asingle measurement module 180 for non-symmetrical right and left totalknee arthroplasty reduces cost and the number of components required. Inone embodiment, the plurality of shims 124 and shims 126 comprise amolded polymer. For example, polymers such as polyurethane, PEEK, orpolycarbonate can be used in an injection molding process to formplurality of shims 124 and shims 126. Similarly, the housing ofmeasurement module 180 can be an injection molded polymer. The use ofnon-symmetrical shims for prosthetic right and left knee joints resultsin an insert that can support the movement and loads of similar to anatural knee joint. Loading, movement, and contact area on the medialand lateral sides of the knee joint are likely not symmetrical.Quantitative measurement data will be used to learn how to distributethe medial-lateral loading and adjust the area, contour, and shape ofthe medial and lateral articular surfaces of the shim to support morenatural movement.

FIG. 2 is an illustration of measurement module 180 with shim 140 andshim 160 in accordance with an example embodiment. Shim 140 is of thefirst type for a prosthetic left knee joint. Shim 160 is of the secondtype for a prosthetic right knee joint. Shim 140 is a 16 millimeter shimfrom plurality of shims 124 shown in FIG. 1 . Shim 160 is a 16millimeter shim from plurality of shims 126 shown in FIG. 1 . Shim 140and shim 160 are not interchangeable. In one embodiment, measurementmodule 180 is configured to couple to shim 140 or shim 160 where shim140 couples to a first side of measurement module 180 and shim 160couples to a second side of measurement module 180. In general pluralityof shims 124 and plurality of shims 126 have at least one retainingfeature configured to retain a shim to measurement module 180. Shim 140has a retaining feature 206 configured to couple to a retaining feature208 on a posterior side of measurement module 180. In one embodiment,retaining feature 206 is a flexible tab having a projection extendingfrom a surface of retaining feature 206. The projection of retainingfeature 206 is configured to couple within a slot or groove 208 ofmeasurement module 180 when shim 140 couples to measurement module 180.In one embodiment, shim 140 and measurement module 180 also haveretaining features on an anterior side. Similarly, shim 160 has aretaining feature 214 configured to couple to retaining feature 208 onthe posterior side of measurement module 180. In one embodiment,retaining feature 214 is a flexible tab having a projection extendingfrom a surface of retaining feature 214. The projection of retainingfeature 214 is configured to couple within a slot or groove 208 ofmeasurement module 180 when shim 160 couples to measurement module 180.In one embodiment, shim 160 and measurement module 180 also haveretaining features on the anterior side. Each of the remaining pluralityof shims 124 and the remaining plurality of shims 126 shown in FIG. 1will respectively couple to measurement module 180 in a similar fashionas shim 140 and shim 160. Retaining feature 208 or retaining feature 214respectively couple to groove 208 of measurement module 180 under force.Measurement module 180 is removed from shim 140 or shim 160 byrespectively bending retaining features 208 or 214 away from groove 208such that measurement module 180 can be removed.

Shim 140 has a medial articular surface 202 and lateral articularsurface 204. Articular medial surface 202 and lateral articular surface204 of shim 140 supports movement of a prosthetic left knee joint. Shim140 is shown overlying measurement module 180 to illustrate theorientation to couple shim 140 to measurement module 180. Medial surface182 and lateral surface 184 of measurement module 180 respectivelycouples to medial articular surface 202 and lateral articular surface204 of shim 140. Thus, the first side of measurement module 180 couplesto shim 140. In one embodiment, measurement module 180 isnon-symmetrical about an anterior-posterior axis. Medial surface 182differs in area, contour, or shape from lateral surface 184 ofmeasurement module 180. Loading applied to medial articular surface 202and lateral articular surface 204 by the femoral prosthetic componentrespectively couples to medial surface 182 and lateral surface 184 ofmeasurement module 180. In one embodiment, measurement module 180measures load magnitude at three or more locations on medial surface 182and at three or more locations on lateral surface 184. The measurementdata is sent to computer 112 of FIG. 1 . Computer 112 of FIG. 1 cancalculate a load magnitude and a position of load in real-time on medialsurface 182 and lateral surface 184 which corresponds to a loadmagnitude and position of load on medial articular surface 202 andlateral articular surface 204.

Shim 160 has a medial articular surface 210 and lateral articularsurface 212. Articular medial surface 210 and lateral articular surface212 of shim 160 supports movement of a prosthetic right knee joint. Shim160 is shown overlying measurement module 180 to illustrate theorientation to couple shim 160 to measurement module 180. Medial surface186 and lateral surface 188 of measurement module 180 respectivelycouples to medial articular surface 210 and lateral articular surface212 of shim 160. Thus, the second side of measurement module 180 couplesto shim 160. In one embodiment, measurement module 180 isnon-symmetrical about an anterior-posterior axis. Medial surface 186differs in area, contour, or shape from lateral surface 188 ofmeasurement module 180. Loading applied to medial articular surface 210and lateral articular surface 212 by the femoral prosthetic componentrespectively couples to medial surface 186 and lateral surface 188 ofmeasurement module 180. In one embodiment, measurement module 180measures load magnitude at three or more locations on medial surface 186and at three or more locations on lateral surface 188. The measurementdata is sent to computer 112 of FIG. 1 . Computer 112 of FIG. 1 cancalculate a load magnitude and a position of load in real-time on medialsurface 186 and lateral surface 188 which corresponds to a loadmagnitude and position of load on medial articular surface 210 andlateral articular surface 212.

FIG. 3 is a top view of shim 140 coupled to measurement module 180 andshim 160 coupled to measurement module 180 in accordance with an exampleembodiment. Shim 140 and measurement module 180 has one or moreretaining features that couples shim 140 to measurement module 180. Theretaining features allow the shim to be released and removed frommeasurement module 180. The first side of measurement module 180 havingmedial surface 182 and lateral surface 184 as shown in FIG. 1 couples toshim 140. Once shim 140 is removed, a different shim of a differentheight from the plurality of shims 124 can be coupled to measurementmodule 180. An anterior-posterior axis is represented by double arrowline 216. Medial articular surface 202 is on medial side of double arrowline 216 and lateral articular surface 204 is on the lateral side ofdouble arrow line 216. Shim 140 is non-symmetrical about theanterior-posterior axis. In the example, medial articular surface 202differs from lateral articular surface 204 by area, contour, or shape.

Measurement module 180 can be removed from shim 140 and coupled to shim160. Shim 160 and measurement module 180 has one or more retainingfeatures that couples shim 160 to measurement module 180. The retainingfeatures allow the shim to be released and removed from measurementmodule 180. The second side of measurement module 180 having medialsurface 186 and lateral surface 188 as shown in FIG. 1 couples to shim160. Once shim 160 is removed, a different shim of a different heightfrom the plurality of shims 126 can be coupled to measurement module180. An anterior-posterior axis is represented by double arrow line 219.Medial articular surface 210 is on a medial side of double arrow line216 and lateral articular surface 212 is on the lateral side of doublearrow line 216. Shim 160 is non-symmetrical about the anterior-posterioraxis. In the example, medial articular surface 210 differs from lateralarticular surface 212 by area, contour, or shape.

FIG. 4 is a bottom view of shim 140 coupled to measurement module 180and a bottom view of shim 160 coupled to measurement module 180 inaccordance with an example embodiment. Medial surface 186 and lateralsurface 188 on the second side of measurement module 180 can be seenfrom the bottom view when coupled to shim 140. Retaining feature 206 ofshim 140 is shown coupling to groove 208 of measurement module 180. Inone embodiment, the projection extending from a surface of retainingfeature 206 of shim 140 fits in the groove 208 of measurement module 180when shim 140 couples to measurement module 180. Shim 140 can be removedfrom measurement module 180 by flexing retaining feature 206 of shim 140away from groove 208 of measurement module 180. Shim 140 can beseparated from measurement module 180 when the projection of retainingfeature 206 is outside groove 208.

Shim 140 can be removed from measurement module 180 and shim 160 coupledto measurement module 180. Medial surface 182 and lateral surface 184 onthe first side of measurement module 180 can be seen from the bottomview when coupled to shim 160. Retaining feature 214 of shim 160 isshown coupling to groove 208 of measurement module 180. In oneembodiment, the projection extending from a surface of retaining feature214 of shim 160 fits in the groove 208 of measurement module 180 whenshim 160 couples to measurement module 180. Shim 160 can be removed frommeasurement module 180 by flexing retaining feature 214 of shim 160 awayfrom groove 208 of measurement module 180. Shim 160 can be separatedfrom measurement module 180 when the projection of retaining feature 214is outside groove 208.

FIG. 5 is an illustration of anterior retaining features for shim 140and measurement module 180 in accordance with an example embodiment. Theanterior retaining and the posterior retaining features in theillustration are also on each shim of plurality of shims 124 and eachshim of plurality of shims 126 of FIG. 1 and couple together withmeasurement module 180 similarly as disclosed herein. Insert 170 has aheight of 16 millimeters when shim 140 is coupled to measurement module180. An anterior of shim 140 has a retaining feature 218 that includes aslot 220. An anterior of measurement module 180 has a post 222configured to fit within slot 220 when coupled together to preventseparation. Also shown is retaining feature 206 of shim 140. Retainingfeature 206 includes projection 216 extending from the surface ofretaining feature 206. Projection 216 fits in groove 208 of measurementmodule 180 as shown in FIG. 2 .

FIG. 6 is an illustration of posterior retaining features for shim 140and measurement module 180 in accordance with an example embodiment.Shim 140 has retaining feature 206 with projection 216 configured to fitin groove 208 of measurement module 180. In one embodiment, post 222 ofmeasurement module 180 is first inserted into opening 220 of retainingfeature 218 of shim 140 of FIG. 5 such that the anterior of shim 140 andmeasurement module 180 are coupled together. The posterior side of shim140 and measurement module 180 can be coupled together by applying acompressive force to shim 140 and measurement module 180. As mentionedpreviously retaining feature 206 is flexible. The compressive forceapplied to shim 140 and measurement module 180 flexes retaining featurepast a surface 250 of measurement module 180 and places projection 216into groove 208 where it retains shim 140 to measurement module 180 toform insert 170. In one embodiment, projection 216 has a contour thatsupports movement and reduces friction of projection 216 as it movesover surface 250 into groove 208. Shim 140 can be rapidly separated frommeasurement module 180 by flexing retaining feature 206 away from groove208 of measurement module 180 and lifting shim 140 away from measurementmodule 180. Retaining feature 206 has to be flexed enough such thatprojection 216 clears the surface 250 of measurement module 180.

FIG. 7 is a bottom view of shim 140 in accordance with an exampleembodiment. The structural elements described herein below will be usedon at least one shim of plurality of shims 124 of FIG. 1 . Shim 140 isof the first type for the left knee joint. Shim 140 has medial articularsurface 202 and lateral articular surface 204 as shown in FIG. 2 .Retaining structure 206 of shim 140 is shown in a distal location ofshim 140 for coupling to measurement module 180 of FIG. 6 . Aspreviously mentioned, retaining structure 206 is flexible. A retainingstructure 208 is shown at an anterior location of shim 140. Retainingstructure 208 includes an opening 220 configured to receive post 222 ofmeasurement module 180 of FIG. 6 . A plurality of columns couple tomedial articular surface 202. Similarly, a plurality of columns coupleto lateral articular surface 204. The plurality of columns that coupleto the medial or lateral articular surface are placed at vertexes of apolygon. Columns 240, 242, and 244 couple to medial articular surface202 of FIG. 2 defining a first triangle and columns 234, 236, and 238couple to lateral articular surface 204 of FIG. 2 defining a secondtriangle. In on embodiment, the first triangle defined by columns 240,242, and 244 corresponds to a first measurement area on medial articularsurface 202 of FIG. 2 . In one embodiment, the second triangle definedby columns 234, 236, and 238 corresponds to a second measurement area onlateral articular surface 204 of FIG. 2 In one embodiment, the firsttriangle or the second triangle has respectively less area than medialarticular surface 202 or the lateral articular surface 204 of FIG. 2 .In one embodiment, load magnitude and position of load can be measuredoutside the first and second triangle areas respectively defined bycolumns 240, 242, and 244 and columns 234, 236, and 238. As mentionedpreviously, medial articular surface 202 of shim 140 differs in area,contour, or shape from lateral articular surface 204 of shim 140.Similarly, the first triangle defined by columns 240, 242, and 244 candiffer by area or shape from the second triangle defined by columns 234,236, and 238.

In general, the area of the first or second triangles are a subsetrespectively of medial articular surface 202 and lateral articularsurface 204 of FIG. 2 . A medial condyle and a lateral condyle of thefemoral prosthetic component respectively couples to medial articularsurface 202 and lateral articular surface 204 of shim 140 as shown inFIG. 1 . In one embodiment, the contact point of the medial or lateralcondyle of the femoral prosthetic component respectively couples withinthe first or second triangle areas over the range of motion. In oneembodiment, the left knee joint could be compromised if a contact pointis outside the polygon defined by columns within each of the pluralityof shims 124.

A structural webbing 232 and 230 is respectively placed within aninterior medial cavity and an interior lateral cavity of shim 140.Structural webbing 232 and 230 stiffens shim 140 and reduces flexing ofshim 140 under loading by the musculoskeletal system. Structural webbing232 couples between a sidewall 254 of shim 140 and columns 240, 242, and244. Structural webbing 232 also couples between columns 240, 242, and244. In one embodiment, structural webbing 232 couples between aninternal wall 248 and columns 240, 242, and 244. Structural webbing 232can also couple between sidewall 254 and internal wall 248. Structuralwebbing 232 also prevents the flexing of columns 240, 242, and 244.

Similarly, structural webbing 230 couples between a sidewall 246 of shim140 and columns 234, 236, and 238. In one embodiment, structural webbing230 couples between an internal wall 252 and columns 234, 236, and 238.Structural webbing 230 can also couple between sidewall 246 and internalwall 252. Structural webbing prevents flexing of columns 240, 242, and244 on the lateral side of shim 140. In one embodiment, columns 240,242, and 244 respectively extend past structural webbing 232 such thatcolumns 240, 242, and 244 couple to medial surface 182 of measurementmodule 180 of FIG. 1 when shim 140 is coupled to measurement module 180.Thus, structural webbing 232 does not couple to medial surface 182 ofmeasurement module 180 of FIG. 1 . In one embodiment, columns 234, 236,and 238 extend past structural webbing 230 such that columns 234, 236,and 238 couple to lateral surface 184 of measurement module 180 of FIG.1 when shim 140 is coupled to measurement module 180. Structural webbing230 does not couple to lateral surface 184 when shim 140 is coupled tomeasurement module 180. In one embodiment, columns 240, 242, and 244couple loading applied to shim 140 to measurement module 180 on themedial side to underlying force, pressure, or load sensors. In oneembodiment, columns 234, 236, and 238 couple loading applied to shim 140on the lateral side to underlying force, pressure, or load sensors.Although shim 140 is used as an example, the structure of shim 140 asdisclosed herein applies to and can be used on each shim of plurality ofshims 124 and plurality of shims 126.

FIG. 8 is an illustration of a top view of shim 150 in accordance withan example embodiment. Shim 150 is a shim from plurality of shims 126 ofthe second type for a right knee joint. Shim 150 corresponds to shim 130of plurality of shims 124 for the left knee joint. Shim 150 is used toillustrate structural elements that can be part of a shim from pluralityof shims 126 or plurality of shims 124 of FIG. 1 . A medial articularsurface 302 and a lateral articular surface 304 is configured to coupleto a femoral prosthetic component to support movement of the right kneejoint. It should be noted that shim 150 is the thinnest shim ofplurality of shims 150. In one embodiment, shim 150 and measurementmodule 180 of FIG. 1 has a height of 10 millimeters when coupledtogether.

FIG. 9 is an illustration of a bottom view of shim 150 in accordancewith an example embodiment. As stated previously, structural elementsdisclosed on shim 150 are used on at least one of plurality of shims 126or at least one of plurality of shims 124 of FIG. 1 . Shim 150 has afirst plurality of columns coupled to medial articular surface 302 and asecond plurality of columns coupled to lateral articular surface 304 ofFIG. 8 . The first plurality of columns and the second plurality ofcolumns are similar to that shown in FIGS. 6 and 7 for shim 140. Shim150 has a sidewall 308 on the medial side and a sidewall 306 on thelateral side. Shim 150 further includes structural webbing 312 andstructural webbing 310 respectively underlying medial articular surface302 and lateral articular surface 304 of FIG. 8 . A plate 314 couples tothe first plurality of columns and the second plurality of columns. Inone embodiment, it has been found that structural webbing 310 and 312does prevent flexing of shim 150 because the height of shim 150 reducesthe depth of structural webbing 310 and 312 thereby reducing theresistance to flexing under loading by a leg. Flexing can introducemeasurement error. In one embodiment, plate 314 is coupled to shim 150to reduce flexing to increase measurement accuracy. In one embodiment,plate 314 is a rigid steel plate. Plate 314 can comprise a rigidpolymer, metal, or metal alloy. Retaining features 316 couple to shim150 to retain plate 314 to shim 150. In one embodiment, plate 314couples to the first plurality of columns and the second plurality ofcolumns that respectively couple to medial articular surface 302 andlateral articular surface 304 of shim 150 of FIG. 8 . In one embodiment,retaining features 316 are rivets that can be glued or welded in placeto retain plate 314 to shim 150. Plate 314 is configured to couple tomedial surface 186 and lateral surface 188 on side 196 of measurementmodule 180 of FIG. 1 .

FIG. 10 is a top view of measurement module 180 in accordance with anexample embodiment. Measurement module 180 comprises a support structure340 and a support structure 342. Support structure 340 and 342 coupletogether to form a housing for electronic circuitry and a plurality ofsensors. Support structure 340 includes a plurality of raised regionsthat extend above medial surface 182 and lateral surface 184. Medialsurface 182 and lateral surface 184 of support structure 340 isconfigured to couple to one of the plurality of shims 124 whichcorrespond to a left prosthetic knee joint. Referring briefly to FIGS. 2and 7 , columns 240, 242, and 244 couple to the medial articular surface202 and columns 234, 236, and 238 couple to the lateral articularsurface 204 of shim 140. As mentioned previously, columns 240, 242, and244 are placed at the vertexes of a first triangle. Columns 234, 236,and 238 are placed at the vertexes of a second triangle. In oneembodiment, columns 244, 242, and 240 respectively correspond to raisedregions 350, 352, and 354 of support structure 340 such that columns 244couples to raised region 350, column 242 couples to raised region 352,and column 240 couples to raised region 354 when shim 140 is coupled tomeasurement module 180. In one embodiment, columns 238, 236, and 234correspond to raise regions 360, 362, and 364 such that column 238couples to raised region 360, column 236 couples to raised region 362,and column 234 couples to raised region 364 when shim 140 is coupled tomeasurement module 180. In general, raised regions 350, 352, and 354 orraised regions 360, 362, and 364 support coupling a load applied to amedial or a lateral articular surface of a shim of the first type tovertexes of a polygon in both the shim and measurement module 180. Inone embodiment, raised regions 350, 352, and 354 are considered part ofmedial surface 182. Similarly, raised regions 360, 362, and 364 areconsidered part of lateral surface 184. Raised regions 350, 352, and 354and raised regions 360, 362, and 364 comprise strengthened regions ofsupport structure 340 to handle loading applied by the musculoskeletalsystem and to minimize flexing. In one embodiment, substantially all ofthe load applied to the medial and lateral articular surfaces of a shimare coupled through the plurality of columns, to the raised regions onsupport structure 340, and finally compressing force, pressure, or loadsensors underlying each raised region of measurement module 180. Themeasurement data

A peripheral raised region 370 is formed around a periphery on themedial side 182 of support structure 340. Similarly, a peripheral raisedregion 372 is formed around a periphery on the lateral side 184 ofsupport structure 340. Peripheral raised region 370 couples to raisedregions 350, 352, and 354. Peripheral raised region 372 couples toraised regions 360, 362, and 364. In one embodiment, peripheral raisedregions 370 and 372 have a same height as raised regions 350, 352, 354,360, 362, and 364. In one embodiment, peripheral raised regions 370, 372and raised regions 350, 352, 354, 360, 362, and 364 are reinforced withmore material to strengthen those areas. Peripheral raised regions 370and 372 coupled between raised regions 350, 352, 354, 360, 362, and 364strengthen support structure 340 to increase rigidity of the raisedregions and reduce flexing.

FIG. 11 is a bottom view of measurement module 180 in accordance with anexample embodiment. Measurement module 180 comprises a support structure340 and a support structure 342. Support structure 342 includes aplurality of raised regions that extend above medial surface 186 andlateral surface 188 configured to couple to a shim of the second typefor a right prosthetic knee joint. In one embodiment, the plurality ofraised regions correspond to the vertexes of a polygon defined by theplurality of columns coupled the medial articular surface and thelateral articular surface of a shim for a right prosthetic knee joint.In one embodiment, raised regions 370, 372, and 374 are at vertexes of afirst triangle corresponding to a plurality of columns coupled to medialarticular surface 210 of shim 160 of FIG. 3 . Similarly, raised regions380, 382, and 384 correspond to a plurality of columns at vertexes of asecond triangle coupled to lateral articular surface 212 of shim 160 ofFIG. 3 . In general, each shim of plurality of shims 126 will have afirst plurality of columns and a second plurality of columnsrespectively coupled to a medial articular surface and a lateralarticular surface. Although the not shown, the first plurality ofcolumns and the second plurality of columns for each shim of pluralityof shims 126 are similar to that shown in FIG. 7 for shim 140 for a leftprosthetic knee joint. In one embodiment, the first plurality of columnsof a shim from plurality of shims 126 of FIG. 1 couple to raised regions370, 372, and 374 of measurement module 180 and the second plurality ofcolumns of the shim from plurality of shims 126 couples to raisedregions 380, 382, and 384 when the shim is coupled to measurement module180. Thus, the load applied to the medial articular surface and thelateral articular surface of the shim of the second type is respectivelycoupled to raised regions 370, 372, and 374 and raised regions 380, 382,and 384 via a first plurality of columns and a second plurality ofcolumns extending from the shim. The first plurality of columns areplaced at vertexes of a first polygon. Similarly, the second pluralityof columns are placed at vertexes of a second polygon. Raised regions370, 372, and 374 and raised regions 380, 382, and 384 comprisestrengthened regions of support structure 342 that support loadingapplied by the musculoskeletal system to the shim and measurement module180 without flexing or distorting.

A peripheral raised region 390 is formed around a periphery on themedial side 186 of support structure 342. Similarly, a peripheral raisedregion 392 is formed around a periphery on the lateral side 188 ofsupport structure 342. Peripheral raised region 390 couples to raisedregions 370, 372, and 374. Peripheral raised region 392 couples toraised regions 380, 382, and 384. In one embodiment, peripheral raisedregions 390 and 392 have a same height as raised regions 370, 372, 374,380, 382, and 384. In one embodiment, peripheral raised regions 390, 392and raised regions 370, 372, 374, 380, 382, and 384 are reinforced withmore material to strengthen those areas. Peripheral raised regions 390and 392 coupled between raised regions 370, 372, 374, 380, 382, and 384strengthen support structure 342 to increase rigidity of the raisedregions and reduce flexing.

FIG. 12 is an exploded view of support structure 340 and supportstructure 342 in accordance with an example embodiment. Supportstructures 340 and 342 form a housing for electronic circuitry 390 andat least one sensor to form measurement module 180. The top view ofsupport structure 340 illustrates raised regions 350, 352, and 354 onmedial surface 182 and raised regions 360, 362, and 364 on lateralsurface 184 of support structure 340. In one embodiment, supportstructure 342 includes one or more cavities to place sensors andelectronic circuitry 390. Electronic circuitry 390 is configured tocontrol a measurement process and to transmit measurement data frommeasurement module 180 to computer 112 as shown in FIG. 1 . Electroniccircuitry 390 is located between sensors 400, 402, and 404 on the medialside and sensors 410, 412, and 414 on the lateral side of supportstructure 342. In one embodiment, electronic circuitry is placed in anunloaded or lightly loaded portion of measurement module 180. Electroniccircuitry 390 can be mounted on and interconnected on a printed circuitboard to form a circuit or system. In one embodiment, the printedcircuit board has multiple layers of interconnect to form the circuit orsystem. Sensors 400, 402, and 404 are coupled to electronic circuitry390 through a flexible interconnect 394 on the medial side of supportstructure 342. Similarly, flexible interconnect 392 couples electroniccircuitry 390 to sensors 410, 412, and 414. In one embodiment, sensors400, 402, 404, 410, 412, and 414 can be integrated within theinterconnect 392 and 394. Sensor integration supports improved sensormatching and reduces variation in performance characteristics of thesensors over different conditions such as time or temperature. In oneembodiment, interconnect 392 and 394 can also include shielding for thesensors and shielding of the interconnect coupling the sensors toelectronic circuitry 390. Shielding reduces parasitic capacitance fromaffecting the sensors. Shielding also reduces the pickup of straysignals that could affect a measurement value. Alternatively, sensors400, 402, 404, 410, 412, and 414 can also be discrete devices thatcouple to interconnect 392 and 394. In one embodiment sensors 400, 402,404, 410, 412, and 414 can be capacitive, piezo, or MEMs load sensors.

Load sensors 400, 402, and 404 respectively align to raised regions 350,352, and 354 of support structure 340. Load sensors 400, 402, and 404respectively align to raised region 370, 372, and 374 of supportstructure 342 of FIG. 11 . In other words, load sensors 400, 402, and404 respectively couple between raised regions 350, 352, 354 of supportstructure 340 and raised regions 370, 372, and 374 of support structure342. Similarly, load sensors 410, 412, and 414 respectively align toraised regions 360, 362, and 364 of support structure 340. Load sensors410, 412, and 414 respectively align to raised regions 380, 382, and 384of support structure 342 of FIG. 11 . Thus, load sensors 410, 412, and414 respectively couple between raised regions 360, 362, 364 of supportstructure 340 and raised regions 380, 382, and 384 of support structure342.

An interconnect 398 couples a first power source to electronic circuitry390 on the medial side of support structure 342. Similarly, aninterconnect 396 couples a second power source to electronic circuitry390 on the lateral side of support structure 342. The first power sourceresides between a portion of medial surfaces 182 and 186 respectively ofsupport structures 340 and 342. The second power source resides betweena portion of lateral surfaces 184 and 188 respectively of supportstructures 340 and 342. The first and second power sources provide powerto measurement module 180 during a surgery. The first and second powersources can be a battery, inductor, capacitor, or other power source. Inone embodiment, loading applied to measurement module does not compressthe first or second power sources as the load is delivered throughcolumns of a shim coupling to raised regions on the measurement module.Interconnect 396 and 398 can be flexible and soldered to the printedcircuit board to which electronic circuitry 390 is mounted.

FIG. 13 is an illustration of an interior of support structure 340 ofmeasurement module 180 of FIG. 10 in accordance with an exampleembodiment. The interior of support structure 340 has a medial interiorsurface 438 and a lateral interior surface 440. Raised regions 420, 422,and 424 are formed on medial interior surface 438. Raised regions 420,422, and 424 respectively align to raised regions 350, 352, and 354 ofFIG. 10 . A peripheral raised region 428 is formed on a periphery ofmedial interior surface 438. In one embodiment, the peripheral raiseregion 428 couples to raised regions 420, 422, and 424. Supportstructure 340 can comprise a polymer such as polyurethane, PEEK,polycarbonate, or other medically approved plastics. Alternatively,support structure 340 can comprise a metal, metal alloy, or a compositematerial.

Loading applied to the articular surface of a shim is transferred toraised regions of medial surface 182 or lateral surface 184. The raisedregions are placed at vertexes of a polygon on medial surface 182 orlateral surface 184. Thus, the load applied to the articular surfaces ofthe shim is transferred to predetermined locations on measurement module180 for a left prosthetic knee joint. The predetermined locations of theraised regions and the load magnitudes measured at each raised regionsare used by computer 112 to calculate the contact point and loadmagnitude where the femoral component couples to medial surface 182 orlateral surface 184 in real-time. In one embodiment, the raised regionssupport coupling at predetermined points as the other portions of medialsurface 182 or lateral surface 184 are at a different height. It is ofbenefit to review a predetermined location or single vertex of supportstructure 340 or support structure 342 of measurement module 180 as theyare all similar. In the example, a predetermined or single vertex of apolygon on measurement module 180 corresponds to raised region 350 onmedial surface 182 of FIG. 10 and raised region 420 on medial interiorsurface 438. Raised region 350 and raised region 420 are respectivelycoupled to other raised regions by peripheral raised region 370 andperipheral raised region 428. The combined thickness of the polymermaterial at the predetermined location or single vertex of a polygon atraised regions 350 and 420 are such that a column of a shim transfersthe load substantially equally across the surface of raised region 350.Raised region 420 then transfers the load substantially equally across aload sensor to which it couples. Each predetermined location or vertexof measurement module 180 operates similarly. In general, the addedthickness of the material at the raised regions of measurement module isrigid under loading to prevent flexing and to distribute the load acrossthe entire sensor surface equally. In one embodiment, the raised regionssuch as raised regions 350 and 420 that respectively couples to a columnof a shim or a sensor has an area larger than or equal to the area ofthe column or sensor. A cavity 444 is formed in medial interior surface438 to provide space to prevent support structure 340 from coupling to apower source when loading is applied to a shim coupled to measurementmodule 180.

Raised regions 430, 432, and 434 are formed on lateral interior surface440. Raised regions 430, 432, and 434 respectively align to raisedregions 360, 362, and 364 of FIG. 10 . A peripheral raised region 436 isformed on a periphery of lateral interior surface 440. In oneembodiment, the peripheral raise region 440 couples to raised regions430, 432, and 434. A further example of the material at a vertex of apolygon comprises raised region 430, support structure 340, and raisedregion 360. The combined thickness of the polymer material at the vertexof the polygon as disclosed herein above is such that when loaded by acolumn of a shim delivers the load substantially equal across thesurface of a load sensor to which raised region 430, support structure340, and raise region 360 couples. The material at the vertex of thepolygon is rigid to prevent flexing under load. Furthermore, the addedmaterial provided by peripheral raised region 436 has been found tofurther reduce flexing at each vertex on lateral interior surface 440 tosupport accurate measurement at each vertex where the loading is appliedto each load sensor by a corresponding column. A cavity 442 is formed inlateral interior surface 440 to provide space to prevent supportstructure 340 from coupling to a power source when loading is applied toa shim coupled to measurement module 180. A tongue 426 couplescircumferentially around a perimeter on an internal side of supportstructure 340. Tongue 426 is configured to couple to a correspondingglue channel in support structure 342 of FIG. 10 . In one embodiment,glue is placed within the glue channel and tongue 426 fits within theglue channel to seal and retain support structure 340 to supportstructure 342 as shown in FIG. 10 .

FIG. 14 is an illustration of an interior of support structure 342 ofmeasurement module 180 of FIG. 10 in accordance with an exampleembodiment. The interior of support structure 342 has a medial interiorsurface 490 and a lateral interior surface 492. Medial interior surface490 and lateral interior surface 492 respectively face medial interiorsurface 438 and lateral interior surface 440 in FIG. 13 when supportstructure 342 couples to support structure 340. Raised regions 450, 452,and 454 are formed on medial interior surface 490 and are raised abovemedial interior surface 490. Similarly, raised regions 460, 462, and 464on lateral interior surface 492 are raised above lateral interiorsurface 492. Raised regions 450, 452, and 454 respectively align toraised regions 420, 422, and 424 of FIG. 13 when support structure 340is coupled to support structure 342. Raised regions 460, 462, and 464respectively align to raised regions 430, 432, and 434 of supportstructure 342 of FIG. 13 . A glue channel 456 is formed by walls 466 and468 around the interior periphery of support structure 342. A tongue 426on support structure 340 of FIG. 13 is configured to fit within gluechannel 456 of support structure 342. Glue channel 456 holds glue toadhere tongue 426 of support structure 340 of FIG. 13 to glue channel456. A peripheral raised region of support structure 342 comprises wall466, tongue 426, and wall 468 when support structure 340 is glued tosupport structure 342. The peripheral raised region surrounds medialinterior surface 490 and lateral interior surface 492. The peripheralraise region of support structure 342 couples to raised regions 450,452, 454, 460, 462, and 464 when support structure 340 is coupled tosupport structure 342. As mentioned previously, support structure 342can comprise a metal, a metal alloy, or a polymer such as polyurethane,PEEK, polycarbonate, or other medically approved plastics.

An example of the material at a vertex of a polygon for measuring loadmagnitude on the medial side comprises raised region 350 (FIG. 10 ),raised region 420 (FIG. 13 ), raised region 450 (FIG. 14 ), and raisedregion 370 (FIG. 11 ). A load sensor is placed between raised region 420of FIG. 13 and raised region 450 of FIG. 14 . Loading applied at thevertex compresses the load sensor. The combined thickness of the polymermaterial at the vertex of the polygon is such that when loaded by acolumn of a shim delivers the load substantially equal across thesurface of a load sensor to which it couples. The material at the vertexof the polygon is rigid to prevent flexing under load. Furthermore, theadded material provided by the peripheral raised region of supportstructure 342 comprising glue channel 456 in combination with tongue 426of FIG. 13 has been found to further reduce flexing at each vertex tosupport accurate measurement at each vertex where the loading is appliedto each load sensor by a corresponding column. Medial interior surfacefurther includes alignment and retaining features 470 and alignment andretaining features 474 configured to support alignment of flexibleinterconnect.

As mentioned previously raised regions 460, 462, and 464 are formed onand above lateral interior surface 492. Raised regions 460, 462, and 464respectively align to raised regions 430, 432, and 434 of supportstructure 340 of FIG. 13 when support structure 340 couples to supportstructure 342. Raised regions 460, 462, and 464 also respectively alignto raised regions 380, 382, and 384 of support structure 342 of FIG. 11.An example of the material at a vertex of a polygon for measuring loadmagnitude on the lateral side comprises raised region 360 (FIG. 10 ),raised region 430 (FIG. 13 ), raised region 460 (FIG. 14 ), and raisedregion 380 (FIG. 11 ). A load sensor is placed between raised region 430of FIG. 13 and raised region 460 of FIG. 14 . Loading applied at thevertex compresses the load sensor on the lateral side. The combinedthickness of the polymer material at the vertex of the polygon is suchthat when loaded by a column of a shim delivers the load substantiallyequal across the surface of a load sensor to which it couples asdisclosed on the medial side herein above. The material at the vertex ofthe polygon is rigid to prevent flexing under load. Furthermore, theadded material provided by the peripheral raised region of supportstructure 342 comprising glue channel 456 in combination with tongue 426of FIG. 13 has been found to further reduce flexing at each vertex tosupport accurate measurement at each vertex where the loading is appliedto each load sensor by a corresponding column. Lateral interior surfacefurther includes alignment and retaining features 472 and alignment andretaining features 476 configured to couple to and retain flexibleinterconnect.

FIG. 15 is an illustration of electronic circuitry 390 in accordancewith and example embodiment. Electronic circuitry 390 is housed inmeasurement module 180 and is configured to control a measurementprocess and to transmit measurement data. In one embodiment, electroniccircuitry 390 is illustrated as a plurality of electronic components. Inone embodiment, electronic circuitry 390 is configured mount to printedcircuit board and the electronic components are configured to beinterconnected by printed circuit board 488. Printed circuit board 488includes one or more layers of interconnect for interconnectingelectronic circuitry 390 to form a circuit or a system. Flexibleinterconnect 398 and 394 couple to printed circuit board 488 from amedial side of measurement module 180. Similarly, flexible interconnect392 and 396 couple to printed circuit board 488 from a lateral side ofmeasurement module 180. In one embodiment, electronic circuitry 390 isplaced in an unloaded region of measurement module 180 between thelateral and medial sides. In one embodiment, flexible interconnect 392,394, 396, and 398 can be solder bumped to printed circuit board 488 forinterconnectivity. At least one sensor couples to electronic circuitry390. The at least one sensor is configured to measure a parameter.

The assembled measurement module 180 of FIG. 10 is configured to measureloading applied to a medial and lateral articular surface of a shim ofthe first type (e.g. left prosthetic knee joint) or the second type(e.g. right prosthetic knee joint). Sensors are housed withinmeasurement module 180 to measure a load magnitude and a position ofload applied to the medial and lateral articular surface by theprosthetic knee joint. In one embodiment, sensors can be integrated intoflexible interconnect 392 and 394 at predetermined locations.Alternatively, sensors can be coupled to flexible interconnect 392 and394 at the predetermined locations. In the example, sensors are placedat vertexes of a polygon. As shown, the sensors are placed at thevertexes of a triangle on the medial side and the lateral side ofmeasurement module 180. More specifically, sensors 400, 402, and 404respectively couple between raised regions 450, 452, and 454 on supportstructure 342 and raised regions 420, 422, and 424 on support structure340 as shown in FIG. 13 . The predetermined locations of sensors 400,402, and 404 on the medial side of measurement module 180 correspond tothe medial surfaces 182 and 186 respectively shown in FIG. 10 and FIG.11 . The predetermined locations also translate to the medial surface ofa shim coupled to measurement module 180.

Similarly, sensors 410, 412, and 414 are placed at vertexes of atriangle on the lateral side of measurement. The vertexes on the lateralside can differ from the vertexes on the medial side such that atriangle formed by the vertexes on the lateral side will differ inshape, area, or geometry from a triangle formed by the vertexes on themedial side of measurement module 180. In one embodiment, measurementmodule 180 is non-symmetrical about the anterior-posterior axis. Morespecifically, sensors 410, 412, and 414 respectively couple betweenraised regions 460, 462, and 464 on support structure 342 and raisedregions 430, 432, and 434 on support structure 340 as shown in FIG. 13 .The predetermined locations of sensors 400, 402, and 404 on the lateralside of measurement module 180 correspond to the medial surfaces 184 and188 respectively shown in FIG. 10 and FIG. 11 . The predeterminedlocations also translate to the lateral surface of a shim coupled tomeasurement module 180.

In one embodiment, at least one retaining feature extends from medialinterior surface 490. The at least one retaining feature couples throughan opening in flexible interconnect 394. The at least one retainingfeature aligns and retains sensors 400, 402, and 404 to raised regions450, 452, and 454 of support structure 342 and raised regions 420, 422,and 424 of support structure 340 of FIG. 13 . In the example, tworetaining features 474 as shown in FIG. 14 extend from support structure342 to couple through openings 482 of flexible interconnect 394.Similarly, at least one retaining at least one retaining feature extendsfrom lateral surface 492. The at least one retaining feature fromlateral surface 492 couples through an opening in flexible interconnect392. The at least one retaining feature aligns and retains sensors 410,412, and 414 to raised regions 460, 462, and 464 of support structure342 and raised regions 430, 432, and 434 of support structure 340 ofFIG. 13 . In the example, two retaining features 476 as shown in FIG. 14extend from support structure 342 to couple through openings 486 offlexible interconnect 392.

Flexible interconnect 398 and flexible interconnect 396 are configuredto respectively couple to power source 494 and power source 496. Powersources 494 and 496 are configured to power measurement module 180 for aprosthetic knee implant operation. Power sources 494 and 496 can becapacitors, inductors, an active power source, or other energy storagedevices. In the example, power source 494 and power source 496 arebatteries that are configured to not be recharged as measurement moduleis a disposable device after the surgery is completed. A terminal 498and a terminal 500 respectively couples to a first electrode and asecond electrode of power source 494. Terminals 500 and 498 have aretaining feature to couple and align flexible interconnect 398 to powersource 494. In the example, terminals 500 and 498 each have a retainingfeature respectively to couple through opening 480 and opening 510 offlexible interconnect 398. Similarly, a terminal 504 couples to a firstelectrode of power source 496 and a terminal 502 couples to a secondelectrode of power source 496. Terminals 504 and 502 have a retainingfeature to couple and align flexible interconnect 396 to power source496. In one embodiment, terminals 498, 500, 502, and 504 have pins thatrespectively couple through openings 510, 480, 484, and 512. In theexample, terminals 504 and 502 each have a retaining featurerespectively to couple through opening 512 and opening 484 of flexibleinterconnect 396. In one embodiment, terminals 500, 494, 504, and 502and flexible interconnect 396 and 398 provide a low resistance path tocouple power sources 496 and 494 to electronic circuitry 390 and printedcircuit board 488. In one embodiment, flexible interconnect 396 and 398configure power sources 496 and 494 in a series configuration.Alternatively, flexible interconnect 396 and 398 can couple powersources 496 and 494 in parallel if required.

The measurement data from sensors 400, 402, 404, 410, 412, and 414 isused to determine a load magnitude applied to a medial articular surfaceand a lateral articular surface of a shim coupled to measurement module180. The measurement data and the predetermined locations of thesensors/raised regions can be used to determine a location of appliedload on the medial articular surface or the lateral articular surface ofthe shim coupled to measurement module 180 by geometry and loadmagnitudes measured by each sensor.

FIG. 16 is a bottom view of shim 160 in accordance with an exampleembodiment. Although, shim 160 is disclosed, the structural elementsdescribed relate to shims 124 of the first type and shims 126 of thesecond type of FIG. 1 . Shim 160 has medial articular surface 210 andlateral articular surface 212. A plurality of columns couple to medialarticular surface 210. Similarly, a plurality of columns couple tolateral articular surface 212. The plurality of columns that couple tothe medial or lateral articular surface are placed at vertexes of apolygon. In one embodiment, columns 540, 542, and 544 couple to medialarticular surface 210 defining a first triangle. Similarly, columns 550,552, and 554 couple to lateral articular surface 212 defining a secondtriangle. In on embodiment, the first triangle defined by columns 540,542, and 544 corresponds to a first measurement area on medial articularsurface 210. In one embodiment, the second triangle defined by columns550, 552, and 554 corresponds to a second measurement area on lateralarticular surface 212. In one embodiment, the first triangle or thesecond triangle has respectively less area than medial articular surface210 or the lateral articular surface 212 of FIG. 2 . In one embodiment,medial articular surface 210 of shim 160 differs in area, contour, orshape from lateral articular surface 212 of shim 160. Similarly, thefirst triangle defined by columns 540, 542, and 544 can differ by areaor shape from the second triangle defined by columns 550, 552, and 554.

In general, the first or second triangles of shim 160 are a subsetrespectively of medial articular surface 210 and lateral articularsurface 212. A medial condyle and a lateral condyle of the femoralprosthetic component respectively couples to medial articular surface210 and lateral articular surface 212 of shim 160. In one embodiment,the contact point of the medial or lateral condyle of the femoralprosthetic component respectively couples within the first or secondtriangle areas over the range of motion of shim 160. In one embodiment,the alignment, stability, and long-term reliability of the prostheticjoint coupling to the musculoskeletal system could be compromised if acontact point is outside the polygon defined by columns of the shimthereby reducing reliability or increasing wear of the prosthetic joint.

A structural webbing 560 and 562 is respectively placed within aninterior medial cavity and an interior lateral cavity of shim 160.Structural webbing 560 and 562 stiffens shim 160 and reduces flexing ofshim 150 under loading by the musculoskeletal system. Structural webbing560 couples between a sidewall 564 of shim 160 and columns 540, 542, and544. Structural webbing 562 also couples between columns 540, 542, and544. In one embodiment, structural webbing 560 couples between aninternal wall 568 and columns 540, 542, and 544. Structural webbing 560can also couple between sidewall 564 and internal wall 568. Structuralwebbing 560 also prevents the flexing of columns 540, 542, and 544.Similarly, structural webbing 562 couples between a sidewall 566 of shim160 and columns 550, 552, and 554. In one embodiment, structural webbing562 couples between an internal wall 570 and columns 550, 552, and 544.Structural webbing 562 can also couple between sidewall 566 and internalwall 570. Structural webbing prevents flexing of columns 550, 552, and554 on the lateral side of shim 160.

In one embodiment, columns 540, 542, and 544 respectively extend paststructural webbing 560 to couple to medial surface 186 of measurementmodule 180 as shown in FIG. 2 . In one embodiment, structural webbing560 does not couple to medial surface 186 of measurement module 180 ofFIGS. 2 and 3 . Columns 550, 552, and 554 extend past structural webbing562 such that columns 550, 552, and 554 couple to lateral surface 188 ofmeasurement module 180 of FIG. 2 when shim 140 is coupled to measurementmodule 180 of FIG. 3 . In one embodiment, structural webbing 562 doesnot couple to lateral surface 188 when shim 160 is coupled tomeasurement module 180. In general, columns 540, 542, and 544 coupleloading applied to shim 160 to measurement module 180 on the medialside. Columns 550, 552, and 554 couple loading applied to shim 160 onthe lateral side.

Shim 160 of plurality of shims 126 as shown in FIG. 1 couples tomeasurement module 180 with the second side having medial surface 186and lateral surface 188 facing and coupling to shim 160 as shown in FIG.2 . In general, loading applied to medial articular surface 210 andlateral articular surface 212 of shim 160 is coupled from thepredetermined locations of the columns in relation to the correspondingsurface to predetermined locations on measurement module 180 as shown inFIG. 3 . In one embodiment, substantially all of the loading is appliedthrough the columns on the medial and lateral sides of the shim tomeasurement module 180. In one embodiment, correction can be applied toa program for calculating load magnitude at each predetermined positionon the medial and lateral articular surfaces for quantifiable losses intransferring load. In the example, columns 540, 542, and 544 couple topredetermined locations on medial surface 186 of measurement module 180.In particular, columns 540, 542, and 544 respectively couple to raisedregions 370, 372, and 374 at the predetermined locations as shown inFIG. 11 . Similarly, columns 550, 552, and 554 couple to predeterminedlocations on lateral surface 188 of measurement module 180. Inparticular, columns 550, 552, and 554 couple respectively couple toraised regions 380, 382, and 384 at the predetermined locations as shownin FIG. 11 . Sensors 400, 402, and 404 respectively underlie raisedregions 370, 372, and 374 of medial surface 186 as shown in FIG. 12 .Sensors 410, 412, and 414 underlie raised regions 380, 382, and 384 oflateral surface 188 as shown in FIG. 12 . Loading applied to shim 160compresses sensors 400, 402, and 400 on the medial side and sensors 410,412, and 414 on the lateral side of measurement module 180 that supportsgenerating a load magnitude of applied force to medial articular surface210 and lateral articular surface 212 of shim 160. Furthermore, eachload magnitude corresponding to medial articular surface 210 and lateralarticular surface 212 provided to computer 110 of FIG. 1 is used tocalculate a contact point of a medial femoral condyle and a lateralfemoral condyle respectively on medial articular surface 210 and lateralarticular surface 212 of shim 160 based on the predetermined locationsand load magnitudes. In one embodiment, the contact points and loadmagnitudes are reported in real-time on display 112 of computer 110 asshown in FIG. 1 .

FIG. 17 is a block diagram of electronic circuitry 390 in measurementmodule 180 as shown in FIG. 12 in accordance with an example embodiment.Electronic circuitry 390 couples to sensors 580. In general, sensors 580comprises a tracking system configured to measure one or more parametersrelated to the musculoskeletal system or in proximity to themusculoskeletal system. For example, sensors 580 can comprise sensors tomeasure, position, slope, rotation, infection, bone density, adhesivesensing, pain, contact point, alignment, color, turbidity, viscosity,photo detection, images, movement, chemicals, sound, and loading to namebut a few. In the example, sensors 580 comprise at least load sensors400, 402, 404, 410, 412, and 414 in measurement module 180. Electroniccircuitry 390 is configured to control a measurement process, receivemeasurement data from all sensors, and transmit the measurement data tocomputer 110 of FIG. 1 for further analysis and feedback. One or moreparameters are measured by sensors 580 coupled to electronic circuitry390 in measurement module 180 when coupled to a shim and inserted into aprosthetic knee joint. In the example, electronic circuitry 390 wouldreceive measurement data from sensors 400, 402, and 404 for measurementof load applied at three predetermined locations on to the medial side ashim and measurement module 180 and sensors 410, 412, and 414 formeasurement of load applied at three predetermined locations on thelateral side of the shim and measurement module 180. Computer 110 canhave a GUI and provide measurement data in a visual, audible, or hapticform that supports rapid assimilation of the data as shown on display112 of computer 110. Electronic circuitry 390 comprises power managementcircuitry 700, control logic 702, memory 704, interface circuitry 706and wireless communication circuitry 720. A power source 582 couples toelectronic circuitry 390 to power a measurement process. In oneembodiment, power source 582 comprises power sources 494 and 496 asshown in FIG. 15 . Electronic circuitry 390 has a small form factor suchthat it can be positioned on or within, or engaged with, or attached oraffixed to or within, a wide range of physical systems including, butnot limited to instruments, equipment, devices, prosthetic components,or other physical systems for use on or in human bodies and configuredfor sensing and communicating parameters of interest in real time.

In general, electronic circuitry 390 is configured to provide two-waycommunication between measurement module 180 and computer 110. Aspreviously mentioned, measurement module 180 can be adapted for use inor on the musculoskeletal system, a prosthetic system, orthopedicequipment, or an orthopedic tool. In one embodiment, measurement module180 provides quantitative measurement data related to a prosthetic kneejoint installation. In one embodiment, measurement module 180 providesquantitative measurement data related to load magnitude, position ofload, position, rotation, tilt, balance, and alignment. In oneembodiment, sensors 580 can include one or more inertial sensors for useas a position tracking system. The measurement data from measurementmodule 180 is used by computer 110 in a kinematic assessment to supportinstallation of prosthetic components to ensure optimal loading,balance, and alignment that improves performance and reliability basedon clinical evidence.

Power source 582 provides power to electronic circuitry 390 and sensors580. The power source 582 can be temporary or permanent. In oneembodiment, the power source can be rechargeable. Charging of the powersource 582 can comprise wired energy transfer or short-distance wirelessenergy transfer. A charging power source to recharge power source 582can include, but is not limited to, a battery or batteries, analternating current power supply, a radio frequency receiver, anelectromagnetic induction coil, a photoelectric cell or cells, athermocouple or thermocouples, or a transducer energy transfer. In oneembodiment, power source 582 has sufficient energy to operate electroniccircuitry 390 in measurement module 180 for an orthopedic surgery with asingle charge. Furthermore, measurement module 180 can utilize powermanagement technologies to minimize the power drain of power source 582while in use or when the system is idling.

In one embodiment, power source 582 in measurement module 180 is abattery or a rechargeable battery. The rechargeable battery can berecharged by the methods disclosed herein above. Alternatively, powersource 582 can be a super capacitor, an inductor, or other energystorage device. An external charging source can be coupled wirelessly tothe rechargeable battery, capacitor, or inductive energy storage devicethrough an electromagnetic induction coil by way of inductive charging.The charging operation can be controlled by power management circuitry700 within electronic circuitry 390. In one embodiment, power managementcircuit 700 supports operation of measurement module 180 during chargingthereby allowing the surgery to continue if a low charge on power source582 is detected. For example, power can be transferred to the battery,capacitive energy storage device, or inductive energy storage device byway of efficient step-up and step-down voltage conversion circuitry.This conserves operating power of circuit blocks at a minimum voltagelevel to support the required level of performance.

Power management circuitry 700 is configured to operate under severepower constraints. In one embodiment, power management circuitry 700controls power up, power down, and minimizes power usage duringoperation. The power management circuitry 700 is configured to reducepower dissipation during operation of the system. The power managementcircuitry 700 can turn off or reduce the power delivered to circuitsthat are not being used in a specific operation. Similarly, if thesystem is idle and not being used, the power management circuitry 700can put other unused circuitry in a sleep mode that awakens prior to thenext measurement being made. Power management circuitry 700 can includeone or more voltage regulation circuits that provide a plurality ofdifferent stable voltages to electronic circuitry 390 and sensors 580.

In one configuration, a charging operation of power source 582 canfurther serve to communicate downlink data to electronic circuitry. Forinstance, downlink control data can be modulated onto the energy sourcesignal and thereafter demodulated from an inductor in electroniccircuitry 390. This can serve as a more efficient way for receivingdownlink data instead of configuring an internal transceiver withinelectronic circuitry 390 for both uplink and downlink operation. As oneexample, downlink data can include updated control parameters thatmeasurement module 180 uses when making a measurement, such as externalpositional information or for recalibration purposes. It can also beused to download a serial number or other identification data.

Control logic 702 controls a measurement process or sequence thatengages the sensors, converts the measurement data into a useableformat, and transmits the information. Control logic 702 can comprisedigital circuitry, a microcontroller, a microprocessor, an ASIC(Application Specific Integrated Circuit), a DSP (Digital SignalProcessing), a gate array implementation, a standard cellimplementation, and other circuitry. Control logic 702 couples to memory704. Memory 704 is configured to store measurement data, softwareroutines, diagnostics/test routines, calibration data, calibrationalgorithms, workflows, and other information or programs. In oneembodiment, one or more sensors may be continuously enabled and controllogic 702 is configured to receive the measurement data, store themeasurement data in memory, or transmit the measurement data. Controllogic 702 can include dedicated ports that couple to a sensor tocontinuously receive measurement data or receive measurement data atdifferent data rates for periodic sampling. Alternatively, control logic702 can select a sensor to be measured. For example, multiple sensorscan be coupled to control logic 702 via a multiplexer. Control logic 702controls which sensor is coupled through the multiplexer to receivemeasurement data. Multiplexed measurement data works well when themeasurement data is not critical or can be sampled occasionally asneeded. Control logic 702 can also select and receive measurement datafrom different sensors in a sequence. Control logic 702 can beconfigured to monitor the measurement data from a sensor but transmitmeasurement data only when a change occurs in the measurement data.Furthermore, control logic 702 can modify the measurement data prior totransmitting the measurement data to computer 110. For example, themeasurement data can be corrected for non-linearity using calibrationdata.

Interface circuitry 706 couples between sensors 580 and control logic702. Interface circuitry 706 supports conversion of a sensor output to aform that can be received by computer 110. Interface circuitry 706comprises digital circuitry and analog circuitry. The analog circuitrycan include multiplexers, amplifiers, buffers, comparators, filters,passive components, analog to digital converters, and digital to analogconverters to name but a few. In one embodiment interface circuitry 706uses one or more multiplexers to select a sensor for providingmeasurement data to control logic 702. Control logic 702 is configuredto provide control signals that enable the multiplexer to select thesensor for measurement. The multiplexer can be enabled to deliver themeasurement data to control logic 702, memory 704, or to be transmitted.Typically, at least one analog to digital conversion or digital toanalog conversion of the measurement data occurs via the interfacecircuitry 706.

Sensors 580 couple through interface circuitry 706 to control logic 702.Alternatively, interface circuitry 706 can couple directly to circuitryfor transmitting measurement data as it is measured. The physicalparameter or parameters of interest measured by sensors 580 can include,but are not limited to, height, length, width, tilt/slope, position,orientation, load magnitude, force, pressure, contact point location,displacement, density, viscosity, pH, light, color, sound, optical,vascular flow, visual recognition, humidity, alignment, rotation,inertial sensing, turbidity, bone density, fluid viscosity, strain,angular deformity, vibration, torque, elasticity, motion, andtemperature. Often, a measured parameter is used in conjunction withanother measured parameter to make a kinetic and qualitative assessment.In joint reconstruction, portions of the muscular-skeletal system areprepared to receive prosthetic components. Preparation includes bonecuts or bone shaping to mate with one or more prosthesis. Parameters canbe evaluated relative to orientation, alignment, direction,displacement, or position as well as movement, rotation, or accelerationalong an axis or combination of axes by wireless sensing modules ordevices positioned on or within a body, instrument, appliance, vehicle,equipment, or other physical system.

Sensors 580 can directly or indirectly measure a parameter of interest.For example, a load sensor in measurement module 180 can comprise acapacitor, a piezo sensor, or a MEMs sensor that can compress as loadingis applied to the load sensor. Measuring load with a capacitor is anindirect form of sensing as the capacitance value of the capacitor willchange with the amount of loading applied to the capacitor. Thecapacitive measurement data can be sent to computer 110 for furtherprocessing. Computer 110 can include software and calibration datarelated to the elastic capacitors. The load measurement data can beconverted from capacitance values to load measurements. Computer 110 canstore calibration data that can be used to curve fit and compensate fornon-linear output of a sensor over a range of operation. Furthermore,the individual sensor measurement can be combined to produce othermeasurement data by computer 110. In keeping with the example of loadmeasurement data, the individual load measurement data can be combinedor assessed to determine a location where the load is applied to asurface to which the load sensors couple. The measurement data can bedisplayed on a display that supports a surgeon rapidly assimilating themeasurement data. For example, the calculated measurement data on thelocation of applied load to a surface may have little or no meaning to asurgeon. Conversely, an image of the surface being loaded with a contactpoint displayed on the surface can be rapidly assimilated by the surgeonto determine if there is an issue with the contact point.

In one embodiment, the orthopedic measurement system transmits andreceives information wirelessly. Wireless operation reduces clutterwithin the surgical area, wired distortion of, or limitations on,measurements caused by the potential for physical interference by, orlimitations imposed by, cables connecting a device with an internalpower with data collection, storage, or display equipment in anoperating room environment. Electronic circuitry 390 includes wirelesscommunication circuitry 720. In one embodiment, wireless communicationcircuitry 720 is configured for short range telemetry and batteryoperation. Typically, measurement module 180, and computer 110 arelocated in an operating room such that the transmission of measurementdata from measurement module 180 to computer 110 is less than 10 meters.As illustrated, the exemplary communications system comprises wirelesscommunication circuitry 720 of measurement module 180 and receivingsystem wireless communication circuitry 722 of computer 110. Wirelesscommunications circuitry 720 comprises, but is not limited to, theantenna 718, a matching network 716, the telemetry transceiver 714, aCRC circuit 712, a data packetizer 710, and a data input 708. Wirelesscommunication circuitry 720 can include more or less than the number ofcomponents shown and is not limited to those shown or the order of thecomponents.

Similarly, computer 110 includes wireless communication circuitry 722.Wireless communication circuitry 722 comprises an antenna 724, amatching network 726, a telemetry receiver 728, a CRC circuit 730, and adata packetizer 732. Notably, other interface systems can be directlycoupled to the data packetizer 732 for processing and rendering sensordata. In general, electronic circuitry 390 couples to sensors 580 and isconfigured to transmit quantitative measurement data to computer 110 inreal-time to process, display, analyze, and provide feedback. In oneembodiment, computer 110 and display 112 is placed just outside thesterile field but in view of the surgical team performing the orthopedicsurgery. Measurement module 180 includes a plurality of load sensorslocated at vertexes of a first polygon on a medial side and a pluralityof load sensors at vertexes of a second polygon on a lateral side. Inone embodiment, measurement module 180 measures load magnitudes withinthe area of the first and second polygons as well as outside the firstand second polygons. In one embodiment, a contact point respectivelywithin the first polygon on the medial side or the second polygon onlateral side of measurement module over a range of motion is anindication that the joint is performing within normal parameters basedon clinical evidence. Conversely, one or more adjustments may berequired if the contact point is found to be outside the first or secondpolygons. The adjustments such as soft tissue tensioning can beperformed in real-time such that the contact point is monitored oncomputer 110 and moved to a desired location on the medial or lateralsurface. In one embodiment, measurement module 180 can measure outsidethe first and second polygons but the measurement accuracy is reduced.In one embodiment, computer 110 can propose a workflow of one or moreadjustments such as bone cuts, soft tissue tensioning, shimming,prosthetic component rotation to adjust the loading or contact point(e.g. position of applied load).

A shim of a first type or a second type is coupled to measurement module180. The shim has a medial articular surface and a lateral articularsurface that transfers loading respectively to the medial surface andthe lateral surface of measurement module 180 for measurement. In oneembodiment, the shim loads measurement module 180 at the vertexes of thefirst and second polygons. Thus, the first and second polygon translatesto the medial articular surface and the lateral articular surface of theshim that is coupled to measurement module 180. Measurement module 180can further include inertial sensors and other parameter measurementsensors. The measurement data from the plurality of load sensors and theinertial sensors is transmitted to computer 110. Computer 110 cancalculate and translate a load magnitude applied to the medial articularsurface and the lateral articular surface of the shim and measured bymeasurement module 180. Computer 110 can further calculate a point ofcontact on the medial articular surface and the lateral articularsurface of the shim coupled to measurement module 180 from the loadmagnitudes measured at the predetermined locations or vertexes of thepolygon on the medial or lateral sides of measurement module 180.Measurement module 180 can further use inertial sensors as a positionmeasurement system or a tracking system. The position or tracking datais also sent to computer 110. The results can also be displayed ondisplay 112 of computer 110. The tracking data can be used to measurethe tibia in relation to the femur, A-P slope, M-L slope, alignment, orprosthetic component rotation. In one embodiment, the transmission ofthe measurement data from different components can be sent on differentchannels or the measurement data can be sent at different times on thesame channel.

As mentioned previously, wireless communication circuitry comprises datainput 708, data packetizer 710, crc circuit 712 telemetry transmitter714, matching network 716, and antenna 718. In general, measurement datafrom sensors 580 is provided to data input 708 of wireless communicationcircuitry 720. In one embodiment, the measurement data from sensors 580can come directly from interface circuitry 706, from memory 704, fromcontrol logic 702, or from a combination of paths to data input 708. Inone embodiment, measurement data can be stored in memory 704 prior tobeing provided to data input 708. The data packetizer 710 assembles themeasurement data into packets; this includes sensor information receivedor processed by control logic 702. Control logic 702 can comprisespecific modules for efficiently performing core signal processingfunctions of the measurement module 180. Control logic 702 provides thefurther benefit of reducing the form factor to meet dimensionalrequirements for integration into measurement module 180.

The output of data packetizer 710 couples to the input of CRC circuit712. CRC circuit 712 applies error code detection on the packet data.The cyclic redundancy check is based on an algorithm that computes achecksum for a data stream or packet of any length. These checksums canbe used to detect interference or accidental alteration of data duringtransmission. Cyclic redundancy checks are especially good at detectingerrors caused by electrical noise and therefore enable robust protectionagainst improper processing of corrupted data in environments havinghigh levels of electromagnetic activity. The output of CRC circuit 712couples to the input of telemetry transceiver 714. The telemetrytransceiver 714 then transmits the CRC encoded data packet through thematching network 716 by way of the antenna 718. Telemetry transceiver714 can increase a carrier frequency in one or more steps and add theinformation or measurement data from measurement module 180 to thecarrier frequency. The matching network 716 provides an impedance matchfor achieving optimal communication power efficiency between telemetrytransmitter 714 and antenna 718.

The antenna 718 can be integrated with components of the measurementmodule 180 to provide the radio frequency transmission. The substratefor the antenna 718 and electrical connections with the electroniccircuitry 390 can further include the matching network 716. In oneembodiment, the antenna 718 and a portion of the matching network 716can be formed in or on printed circuit board 488 of FIG. 15 thatinterconnects the components that comprise electronic circuitry 390.This level of integration of the antenna and electronics enablesreductions in the size and cost of wireless equipment. Potentialapplications may include, but are not limited to any typemusculoskeletal equipment or prosthetic components where a compactantenna can be used. This includes disposable modules or devices as wellas reusable modules or devices and modules or devices for long-term use.Wireless communication can be on a scientific band, medical band, opencommunication band, or a low power short range band such as Bluetooth.

The process for receiving wireless communication circuitry 722 is theopposite of the sending process. Antenna 724 receives transmittedmeasurement data from wireless communication circuitry 720. Wirelesscommunication circuitry 720 can transmit at low power such thatreceiving wireless communication circuitry 722 must be in proximity, forexample within 10 meters to receive measurement data. Antenna 724couples to matching network 726 that efficiently couples the measurementdata to telemetry transmitter circuit 728. The measurement data can besent on a carrier signal that supports wireless transmission. Themeasurement data is stripped off from the carrier signal by telemetrytransmitter 728. The measurement data is received by CRC circuit 730from telemetry transmitter 728. CRC circuit 730 performs a cyclicredundancy check algorithm to verify that the measurement data has notbeen corrupted during transmission. The CRC circuit 730 provides thechecked measurement data to data packetizer 732. Data packetizer 732reassembles the measurement data where it is provided to usb interface734. USB interface 734 provides the measurement data to computer 110 forfurther processing.

It should be noted that the measuring, transmitting, receiving, andprocessing of the measurement data can be performed in real-time for useby a surgeon installing prosthetic join in a surgical environment. Inone embodiment, computer 110 displays at least a portion of oneprosthetic component. In the example, the medial articular surface andthe lateral articular surface of a shim of the first type is displayedon display 112. The medial articular surface includes a polygon 738 ondisplay 112. The lateral articular surface includes a polygon 740 ondisplay 114. As mentioned previously, polygon 738 can differ frompolygon 740 by area, contour, or shape. In one embodiment, load sensorsunderlie the vertexes of polygon 738 and polygon 740 within measurementmodule 180. In the example, polygons 738 and 740 are drawn as a triangleand shown in display 112. Note that polygons 738 and 740 are a subset orsmaller than the medial articular surface or the lateral articularsurface of the shim. Polygon 738 can differ in shape, size, or contourfrom polygon 740. Measurement data from the load sensors is used tocalculate a load magnitude and a position of applied load on the medialor lateral surface of the shim. The location of each load sensor isknown relative to the medial or lateral articular surfaces of the shim.The position of applied load can be calculated using the locationinformation of each load sensor and the load magnitude at each vertex bycomputer 110. Similarly, the load magnitude at the position of appliedload can be calculated from the load magnitudes at the vertexes ofpolygon 738 or 740. In the example, a femoral prosthetic componentcouples to the shim and measurement module in the prosthetic knee joint.The femoral prosthetic component has a medial condyle and a lateralcondyle that respectively couples to the medial articular surface andthe lateral articular surface of the shim. The medial condyle couples tothe shim at contact point 742 as shown on display 112. Similarly, thelateral condyle couples to the shim at contact point 744 as shown ondisplay 112. Medial load magnitude 746 and lateral load magnitude 748are indicated in display boxes on display 112. The amount of rotation ofthe shim and measurement module can also be measured with the positionmeasurement system. The amount of rotation is indicated by rotation 736on display 112. These measurements are measured or calculated inreal-time. Adjustments can be performed that affects alignment, loading,position of load, rotation, or other parameters and monitored inreal-time on display 112. The adjustments can support optimization afterthe measured parameters are within specification to fine tune theprosthetic component installation with quantitative measurement data.

FIG. 18 is a block diagram of a measurement system or computer inaccordance with an example embodiment. The exemplary diagrammaticrepresentation of a machine, system, or computer in the form of a system600 within which a set of instructions, when executed, may cause themachine to perform any one or more of the methodologies discussed above.In some embodiments, the machine operates as a standalone device. Insome embodiments, the machine may be connected (e.g., using a network)to other machines. In a networked deployment, the machine may operate inthe capacity of a server or a client user machine in server-client usernetwork environment, or as a peer machine in a peer-to-peer (ordistributed) network environment.

The machine may comprise a server computer, a client user computer, apersonal computer (PC), a tablet PC, a laptop computer, a desktopcomputer, a control system, logic circuitry, a sensor system, an ASIC,an integrated circuit, a network router, switch or bridge, or anymachine capable of executing a set of instructions (sequential orotherwise) that specify actions to be taken by that machine. It will beunderstood that a device of the present disclosure includes broadly anyelectronic device that provides voice, video or data communication.Further, while a single machine is illustrated, the term “machine” shallalso be taken to include any collection of machines that individually orjointly execute a set (or multiple sets) of instructions to perform anyone or more of the methodologies discussed herein.

System 600 may include a processor 602 (e.g., a central processing unit(CPU or DSP), a graphics processing unit (GPU, or both), a main memory604 and a static memory 606, which communicate with each other via a bus608. System 600 may further include a video display unit 610 (e.g., aliquid crystal display (LCD), a flat panel, a solid state display, or acathode ray tube (CRT)). System 600 may include an input device 612(e.g., a keyboard), a cursor control device 614 (e.g., a mouse), a diskdrive unit 616, a signal generation device 618 (e.g., a speaker orremote control) and a network interface device 620.

The disk drive unit 616 can be other types of memory such as flashmemory and may include a machine-readable medium 622 on which is storedone or more sets of instructions 624 (e.g., software) embodying any oneor more of the methodologies or functions described herein, includingthose methods illustrated above. Instructions 624 may also reside,completely or at least partially, within the main memory 604, the staticmemory 606, and/or within the processor 602 during execution thereof bythe system 600. Main memory 604 and the processor 602 also mayconstitute machine-readable media.

Dedicated hardware implementations including, but not limited to,application specific integrated circuits, programmable logic arrays andother hardware devices can likewise be constructed to implement themethods described herein. Applications that may include the apparatusand systems of various embodiments broadly include a variety ofelectronic and computer systems. Some embodiments implement functions intwo or more specific interconnected hardware modules or devices withrelated control and data signals communicated between and through themodules, or as portions of an application-specific integrated circuit.Thus, the example system is applicable to software, firmware, andhardware implementations.

In accordance with various embodiments of the present disclosure, themethods described herein are intended for operation as software programsrunning on a computer processor. Furthermore, software implementationscan include, but not limited to, distributed processing orcomponent/object distributed processing, parallel processing, or virtualmachine processing can also be constructed to implement the methodsdescribed herein.

The present disclosure contemplates a machine readable medium containinginstructions 624, or that which receives and executes instructions 624from a propagated signal so that a device connected to a networkenvironment 620 can send or receive voice, video or data, and tocommunicate over the network 626 using the instructions 624. Theinstructions 624 may further be transmitted or received over the network626 via the network interface device 620.

While the machine-readable medium 622 is shown in an example embodimentto be a single medium, the term “machine-readable medium” should betaken to include a single medium or multiple media (e.g., a centralizedor distributed database, and/or associated caches and servers) thatstore the one or more sets of instructions. The term “machine-readablemedium” shall also be taken to include any medium that is capable ofstoring, encoding or carrying a set of instructions for execution by themachine and that cause the machine to perform any one or more of themethodologies of the present disclosure.

The term “machine-readable medium” shall accordingly be taken toinclude, but not be limited to: solid-state memories such as a memorycard or other package that houses one or more read-only (non-volatile)memories, random access memories, or other re-writable (volatile)memories; magneto-optical or optical medium such as a disk or tape; andcarrier wave signals such as a signal embodying computer instructions ina transmission medium; and/or a digital file attachment to e-mail orother self-contained information archive or set of archives isconsidered a distribution medium equivalent to a tangible storagemedium. Accordingly, the disclosure is considered to include any one ormore of a machine-readable medium or a distribution medium, as listedherein and including art-recognized equivalents and successor media, inwhich the software implementations herein are stored.

Although the present specification describes components and functionsimplemented in the embodiments with reference to particular standardsand protocols, the disclosure is not limited to such standards andprotocols. Each of the standards for Internet and other packet switchednetwork transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) representexamples of the state of the art. Such standards are periodicallysuperseded by faster or more efficient equivalents having essentiallythe same functions. Accordingly, replacement standards and protocolshaving the same functions are considered equivalents.

FIG. 19 is an illustration of a communication network 700 formeasurement and reporting in accordance with an exemplary embodiment.Briefly, the communication network 700 expands broad data connectivityto other devices or services. As illustrated, the measurement andreporting system 702 can be communicatively coupled to thecommunications network 700 and any associated systems or services.System 702 corresponds to orthopedic measurement system 100 of FIG. 1configured to measure one or more parameters related to themusculoskeletal system or in proximity to the musculoskeletal system.Communication network 700 supports two-way communication of orthopedicmeasurement system 100 to another system or database. As one example,measurement system 702 can share its parameters of interest (e.g.,angles, load, balance, distance, alignment, displacement, movement,rotation, and acceleration) with remote services or providers, forinstance, to analyze or report on surgical status or outcome. This datacan be shared for example with a service provider to monitor progress orwith plan administrators for surgical monitoring purposes or efficacystudies. The communication network 700 can further be tied to anElectronic Medical Records (EMR) system to implement health informationtechnology practices. In other embodiments, the communication network700 can be communicatively coupled to HIS Hospital Information System,HIT Hospital Information Technology and HIM Hospital InformationManagement, EHR Electronic Health Record, CPOE Computerized PhysicianOrder Entry, and CDSS Computerized Decision Support Systems. Thisprovides the ability of different information technology systems andsoftware applications to communicate, to exchange data accurately,effectively, and consistently, and to use the exchanged data.

The communications network 700 can provide wired or wirelessconnectivity over a Local Area Network (LAN) 704, a Wireless Local AreaNetwork (WLAN) 710, a Cellular Network 706, and/or other radio frequency(RF) system. The LAN 704 and WLAN 710 can be communicatively coupled tothe Internet 708, for example, through a central office. The centraloffice can house common network switching equipment for distributingtelecommunication services. Telecommunication services can includetraditional POTS (Plain Old Telephone Service) and broadband servicessuch as cable, HDTV, DSL, VoIP (Voice over Internet Protocol), IPTV(Internet Protocol Television), Internet services, and so on.

The communication network 700 can utilize common computing andcommunications technologies to support circuit-switched and/orpacket-switched communications. Each of the standards for Internet 708and other packet switched network transmission (e.g., TCP/IP, UDP/IP,HTML, HTTP, RTP, MMS, SMS) represent examples of the state of the art.Such standards are periodically superseded by faster or more efficientequivalents having essentially the same functions. Accordingly,replacement standards and protocols having the same functions areconsidered equivalent.

The cellular network 706 can support voice and data services over anumber of access technologies such as GSM-GPRS, EDGE, CDMA, UMTS, WiMAX,2G, 3G, WAP, software defined radio (SDR), and other known technologies.The cellular network 706 can be coupled to base receiver 712 under afrequency-reuse plan for communicating with mobile devices 714.

The base receiver 712, in turn, can connect the mobile device 714 to theInternet 708 over a packet switched link. The internet 708 can supportapplication services 724 and service layers for distributing data fromthe measurement system 702 to the mobile device 714. Mobile device 714can also connect to other communication devices through the Internet 708using a wireless communication channel.

The mobile device 714 can also connect to the Internet 708 over the WLAN710. Wireless Local Access Networks (WLANs) provide wireless accesswithin a local geographical area. WLANs are typically composed of acluster of Access Points (APs) 716 also known as base stations. Themeasurement system 700 can communicate with other WLAN stations such aslaptop 718 within the base station area. In typical WLANimplementations, the physical layer uses a variety of technologies suchas 802.11ac or 802.11n WLAN technologies. The physical layer may useinfrared, frequency hopping spread spectrum in the 2.4 GHz Band, directsequence spread spectrum in the 2.4 GHz Band, or other accesstechnologies, for example, in the 5.8 GHz ISM band or higher ISM bands(e.g., 24 GHz, etcetera).

By way of the communication network 700, the measurement system 702 canestablish connections with a remote server 720 on the network and withother mobile devices for exchanging data. The remote server 720 can haveaccess to a database 722 that is stored locally or remotely and whichcan contain application specific data. The remote server 720 can alsohost application services directly, or over the Internet 708.

FIG. 20 is an illustration of orthopedic measurement system 100including a handle and a tibial prosthetic component 800 in accordancewith an example embodiment. Tibial prosthetic component 800 is used tosupport measurement and placement of an insert on a tibia 810. Theinsert of orthopedic measurement system 100 comprises a shim fromplurality of shims 124 or plurality of shims 126 coupled to measurementmodule 180 of FIG. 1 . Tibial prosthetic component 800 is a trialingdevice that is used before a final tibial prosthetic component is fittedto tibia 810. Tibial prosthetic component 800 has substantially equaldimensions as the final tibial prosthetic component such that a finalinstallation of the final tibial prosthetic component and a final insertwill have substantially equal measurement data as generated bymeasurement module 180 of FIG. 1 .

A proximal end of tibia 810 has a prepared bone surface 812. In oneembodiment, prepared surface 812 is perpendicular to the mechanical axisof the leg. Alternatively, prepared surface 812 can be prepared havingan anterior-posterior slope, a medial-lateral slope, or both. Tibialprosthetic component 800 couples to the prepared bone surface 812. Inone embodiment, tibial prosthetic component 800 can be of a first typefor a left knee joint or a second type for a right knee joint. In theexample, the first and second types are non-symmetrical and can only beused for the designated knee (e.g. left knee or right knee). Tibialprosthetic component 800 can be temporarily retained to prepared surface812 of tibia 810. In one embodiment, an opening 802 and an opening 804are formed in tibial prosthetic component 800. A screw or nail cancouple through opening 802 or opening 804 into tibia 810 to temporarilyretain tibial prosthetic component 800 to prepared surface 812 of tibia810.

A handle 806 is configured to couple to tibial prosthetic component 800.Handle 806 can be used to place tibial prosthetic component 800 at areference position on prepared surface 812 of tibia 810. In oneembodiment, the reference position can correspond to a rotation of zerodegrees relative to the reference position. Handle 806 can also be usedto move tibial prosthetic component 800 to a different position. In oneembodiment, handle 806 is used to rotate tibial prosthetic component 806from the reference position. Handle 806 further includes a control 808that is configured to lock or unlock handle 806 to tibial prostheticcomponent 800. As mentioned previously, measurement module 180 of FIG. 1includes a tracking or position measurement system. In one embodiment,the tracking or position measurement system comprises one or moreinertial sensors in measurement module 180. The insert comprising theshim coupled to measurement module 180 of FIG. 1 couples to tibialprosthetic component 180. Thus, as tibial prosthetic component 800 isrotated by handle 806 from a reference position, it is measured inreal-time by measurement module 180 and sent to computer 110 anddisplayed on display 112 as shown in FIG. 17 . In one embodiment,rotating the insert changes alignment, position of load, and loadmagnitude on the medial and lateral articular surface of the shim, andposition of the insert all of which is quantitatively measured.

FIG. 21 is an illustration of tibial prosthetic component 800 inaccordance with an example embodiment. Tibial prosthetic component 800includes openings 816 and 818 that couple to handle 806 of FIG. 20 . Inone embodiment, handle 806 has a first retaining feature and a secondretaining feature that is respectively inserted into openings 816 and818. Tibial prosthetic component 800 further includes an opening 820configured to lock handle 806 to tibial prosthetic component 800. In oneembodiment, a retaining tab locks into opening 820 thereby preventinghandle 806 from being separated from tibial prosthetic component 800.Control 808 of FIG. 20 on handle 800 releases the retaining tab fromopening 820 thereby allowing handle 806 of FIG. 20 to be removed fromtibial prosthetic component 800. As shown, a nail 814 is configured tocouple through opening 802 and into tibia 810 of FIG. 20 . Nail 814holds tibial prosthetic component 800 to a tibia but allows tibialprosthetic component 800 to rotate. As mentioned, tibial prostheticcomponent 800 can be rotated and the amount of rotation measured bymeasurement module 180 from the reference position to change alignment,position of load or load magnitude for optimization of the knee jointinstallation. A second nail can be coupled through opening 804 intotibia 810 to fix a position of tibial prosthetic component 800 and theinsert for further measurement or adjustment. In one embodiment, theopenings formed by nail 814 and the second nail in prepared surface 812of FIG. 20 are used to align a final tibial prosthetic component 800 totibia 810 in the same position as tibial prosthetic component 800.

FIG. 22 is an illustration of an insert coupled to tibial prostheticcomponent 800 in accordance with an example embodiment. In the example,the insert comprises shim 140 of a first type of plurality of shims 124coupled to a first side of measurement module 180 briefly referring toFIGS. 2 and 3 . Shim 140 has medial articular surface 202 and lateralarticular surface 204. The second side of measurement module 180 couplesto and is retained by tibial prosthetic component 800. Each shim of theplurality of shims can be used to couple to the first side ofmeasurement module 180 to yield an insert of a different height. In oneembodiment, the first side or the second side of measurement module 180can couple to tibial prosthetic component 180.

Alternatively, a second tibial prosthetic component can be provided withthe system for an insert comprising a shim of the second type coupled tothe second side of measurement module 180. The first side of measurementmodule 180 couples to the second tibial prosthetic component. In oneembodiment, the first tibial prosthetic component 800 couples to a lefttibia and the second tibial prosthetic component couples to the righttibia. Shim 140 further comprises openings 822 and 824. Referringbriefly to FIG. 20 , handle 806 can couple to openings 822 and 824 thatare similar to openings 816 and 818 of FIG. 21 . Similarly, theretaining tab of handle 806 can lock into opening 826 of shim 140 toretain handle 806 shim 140. Handle 806 can be used to place or move theinsert. Each shim of plurality of shims 124 and plurality of shims 126of FIG. 1 has similar openings to 822, 824, and 826 to support couplingof handle 806 to each shim or insert.

Referring briefly to FIGS. 1, 2, 4, 7, 10, and 15 a shim of a first typecouples to measurement module 180. The first type corresponds to one ormore prosthetic components or parts for prosthetic components for a leftleg or left knee joint. In one embodiment, parts of the first typecannot be used on a right leg or right knee joint. Shim 140 has a firstplurality of columns and a second plurality of columns respectivelycoupled to medial surface 202 and lateral surface 204 of shim 140. Thefirst plurality of columns and the second plurality of columnsrespectively couple to medial surface 182 and lateral surface 184 ofmeasurement module 180. In one embodiment, medial surface 182 andlateral surface 184 correspond to a first side of measurement module180. Shim 140 is an example of how a shim of plurality of shims 124couples to measurement module 180 to measure loading and position ofload. As mentioned previously, shim 140 is 16 millimeter shim fromplurality of shims 124. In one embodiment, shim 140 comprises columns240, 242, and 244 on the medial side and columns 234, 236, and 238 onthe lateral side of shim 140. Measurement module 180 is configured tomeasure loading applied to medial articular surface 202 and lateralarticular surface 204 of shim 140 when coupled together. In oneembodiment, medial surface 182 on a first side of measurement module 180differs in area, contour, or shape from lateral surface 184 on the firstside of measurement module 180. In one embodiment, medial articularsurface 202 differs in area, contour, or shape than lateral articularsurface 204 of shim 140. In one embodiment, load sensors 400, 402, and404 of measurement module 180 are configured to be respectively alignedto and underlie columns 244, 242, and 240 of shim 140 when the firstside of measurement module 180 couples to shim 140. Similarly, loadsensors 410, 412, and 414 are configured to be respectively aligned toand underlie columns 238, 236, and 234 of shim 140 when the first sideof measurement module 180 couples to shim 140. Load sensors 400, 402,404, 410, 412, and 414 can be a capacitor, a piezo sensor, or a MEMssensor formed in the interconnect or coupled to the interconnect.

Referring briefly to FIGS. 1, 2, 4, 11, and 16 a shim of a second typecouples to measurement module 180. The second type corresponds to one ormore prosthetic components or parts for prosthetic components for aright leg or right knee joint. In one embodiment, the shim of the secondtype cannot be used on a left leg or left knee joint. Shim 160 has afirst plurality of columns and a second plurality of columnsrespectively coupled to medial surface 210 and lateral surface 212 ofshim 160. The first plurality of columns and the second plurality ofcolumns of shim 160 respectively couple to medial surface 186 andlateral surface 188 of measurement module 180. In one embodiment, medialsurface 186 and lateral surface 188 correspond to a second side ofmeasurement module 180. Shim 160 is an example of how a shim ofplurality of shims 126 couples to measurement module 180. As mentionedpreviously, shim 160 is 16 millimeter shim from plurality of shims 126.In one embodiment, shim 160 comprises columns 540, 542, and 544 on themedial side and columns 550, 552, and 554 on the lateral side of shim160. Measurement module 180 is configured to measure loading applied tomedial articular surface 210 and lateral articular surface 212 of shim160 when coupled together. The position of load or contact point can bemeasured from the measurement data using the predetermined locations ofcolumns 540, 542, 544, 550, 552, and 554 relative to medial surface 210and lateral surface 212. In one embodiment, medial surface 186 on asecond side of measurement module 180 differs in area, contour, or shapefrom lateral surface 188 on the second side of measurement module 180.In one embodiment, medial articular surface 210 differs in area,contour, or shape than lateral articular surface 212 of shim 160. In oneembodiment, load sensors 400, 402, and 404 of measurement module 180 areconfigured to be respectively aligned to and underlie columns 540, 542,and 544 of shim 160 when the second side of measurement module 180couples to shim 160. Similarly, load sensors 410, 412, and 414 areconfigured to be respectively aligned to and underlie columns 550, 552,and 554 of shim 160 when the second side of measurement module 180couples to shim 160.

Referring briefly to FIGS. 12 and 15 , at least three load sensors arecoupled between medial surface 182 and medial surface 186 of measurementmodule 180. In the example, load sensors 400, 402, and 404 couplebetween medial surface 182 and medial surface 186 of measurement module180. Load sensors 400, 402, and 404 are placed at vertexes of a firsttriangle. Similarly, at least three load sensors are coupled betweenlateral surface 184 and lateral surface 188 of measurement module 180.In the example, load sensors 410, 412, and 414 couple between lateralsurface 184 and lateral surface 188 of measurement module 180. Loadsensors 410, 412, and 414 are placed at vertexes of a second triangle.The exact position of each load sensor is known within measurementmodule 180, relative to medial surfaces 182 and 186, relative to lateralsurfaces 184 and 188, and relative to the medial and lateral articularsurfaces of any shim from shims 124 and shims 126. The position data ofthe each load sensor is provided to computer 110 to support calculationof the position of load or contact point. The first and second trianglescorrespond to the location of the load sensors on the medial or lateralsides of measurement module 180 and can differ in shape and area.Electronic circuitry 390 couples to the at least three load sensorscoupled between medial surface 182 and medial surface 186. In theexample, interconnect 394 couples load sensors 400, 402, and 404 toelectronic circuitry 390. Similarly, electronic circuitry 390 couples tothe at least three load sensors coupled between lateral surface 184 andlateral surface 188. In the example, interconnect 392 couples loadsensors 410, 412, and 414 to electronic circuitry 390. Electroniccircuitry 390 can be mounted on a printed circuit board 488. Electroniccircuitry 390 and load sensors 400, 402, 404, 410, 412, and 414 arehermetically sealed from an external environment when support structure340 and support 342 are coupled together. Electronic circuitry 390supports a measurement process and transmits measurement data to acomputer. The computer can have a display to provide the measurementdata in real-time.

Electronic circuitry 390 is powered by power source 494 and power source496. Power sources 494 and 496 respectively underlie at least a portionof medial surface 182 and at least a portion of lateral surface 184. Inone embodiment, power sources 494 and 496 are not under compression whenmeasurement module 180 is under load. In one embodiment, at least aportion of power source 494 couples between medial surface 182 ofsupport structure 340 and medial surface 186 of support structure 342.In one embodiment, at least a portion of power source 496 couplesbetween lateral surface 184 of support structure 340 and lateral surface188 of support structure 342 Interconnect 398 couples power source 494to electronic circuitry 390. In one embodiment, interconnect 398 couplesto printed circuit board 488. Interconnect 396 couples power source 496to electronic circuitry 390. In one embodiment, interconnect 396 couplesto printed circuit board 488. Measurement module 180 can be used in asurgical environment. Power sources 494 and 496 have sufficient power toenable electronic circuitry 390 for an extended surgery such as a jointinstallation.

Referring to FIGS. 1, 2, 3, 12, and 15 a plurality of shims 124 of afirst type and a plurality of shims 126 of a second type are providedwith the knee measurement system. In one embodiment, plurality of shims124 of the first type are for a left leg or left knee joint andplurality of shims 126 of the second type are for a right leg or rightknee joint. Each shim of plurality of shims 124 and plurality of shims126 has a medial articular surface and a lateral articular surface. Asmentioned previously, plurality of shims 124 cannot be used on a rightknee joint and plurality of shims 126 cannot be used on a left kneejoint. Each shim of plurality of shims 124 is non-symmetrical about theanterior-posterior axis. Each shim of plurality of shims 126 isnon-symmetrical about the anterior-posterior axis. In general, themedial articular surface differs from the lateral articular surface of ashim in area, contour, or shape. Each shim of plurality of shims 124 and126 have a plurality of columns extending from a medial articularsurface and a plurality of columns extending from a lateral articularsurface similar to that disclosed for shim 140 and shim 160 hereinabove. The position or location of the plurality of columns coupled tothe medial articular surface or the lateral articular surface of eachshim is known and correspond to vertexes of a polygon as disclosedherein above. Each column of the plurality of columns coupled to themedial articular surface or the lateral articular surface of each shimare configured to couple to corresponding sensor located in measurementmodule 180.

Measurement module 180 has medial surface 182 and lateral surface 184 ona first side. Measurement module 180 has a medial surface 186 and alateral surface 188 on a second side. Each shim of plurality of shims124 couples to the first side of measurement module 180. Each shim ofplurality of shims 126 couples to the second side of measurement module180. Load sensors are placed at vertexes of a first polygon on a medialside of measurement module 180. Load sensors are placed at vertexes of asecond polygon on a lateral side of measurement module 180. In oneembodiment, the first polygon defines an area of measurement on themedial side of measurement module 180 and on a medial articular surfaceof a shim coupled to measurement module 180. In one embodiment, thesecond polygon defines an area of measurement on the lateral side ofmeasurement module 180 and on a lateral articular surface of the shimcoupled to measurement module 180. Measurement data from each loadsensor on the medial side and the lateral side of measurement module 180is sent by wire or wireless transmission. In the example, the shim andmeasurement module 180 is used in an operating room to providemeasurement data on a knee joint application. Computer 110 havingdisplay 112 is configured to receive the measurement data frommeasurement module 180 wirelessly in real-time and to display themeasurement data within the surgical environment for a surgical team.The computer uses the measurement data to determine the load magnitudeapplied to the medial articular surface of the shim and the loadmagnitude applied to the lateral articular surface of the shim whencoupled to measurement module 180 and placed in the prosthetic kneejoint. The computer can further identify the point of contact on themedial articular surface of the shim and the lateral articular surfaceof the shim. Measurement module 180 can further include a trackingsystem to monitor position, location, movement, rotation, angle, orslope. In one embodiment, the tracking system can comprise one or moreinertial sensors configured to track position or location on at leastone prosthetic component of the prosthetic knee joint. Measurementmodule 180 can further support real-time change in the prosthetic kneejoint with quantitative measurement. For example, soft tissue tensioningcan be used to change load or position of load on the medial or lateralarticular surface of the shim in real-time. Computer 110 and display 112can display changes as the tissue is cut. Similarly, prostheticcomponents can be rotated or bone cuts can be made that changesprosthetic component orientation, loading, and position of load. Theamount of rotation, change in slope, or position of the prostheticcomponents can be monitored in real-time.

Referring briefly to FIGS. 1, 12, and 15 , measurement module 180includes a first sensor, a second sensor, a third sensor, a fourthsensor, a fifth sensor, and a sixth sensor respectively corresponding toload sensors 400, 402, 404, 410, 412, and 414. In one embodiment loadsensors 400, 402, 404, 410, 412, and 414 are capacitors, MEMs loadsensors, piezo load sensors, strain gauges, or other sensor types thatmeet the form factor for a prosthetic component. Load sensors 400, 402,and 404 are placed at a first vertex, a second vertex, and a thirdvertex of a first triangle. Load sensors 400, 402, and 404 are placedbetween medial surface 182 and medial surface 186 of measurement module180. Similarly, load sensors 410, 412, and 414 are respectively placedat a fourth vertex, fifth vertex, and a sixth vertex of a secondtriangle. Load sensors 410, 412, and 414 are placed between lateralsurface 184 and 188 of measurement module 180 at the vertexes. Medialsurface 182 and lateral surface 184 is on a first side of measurementmodule 180. Medial surface 186 and lateral surface 188 is on a secondside or measurement module 180. In one embodiment, the first trianglediffers from the second triangle in area, contour, or shape.

Electronic circuitry 390 is coupled to the first, second, third, fourth,fifth, and six sensors and is configured to control a measurementprocess and transmit measurement data. In one embodiment, sensor 410 Inone embodiment, load sensors 400, 402, and 404 couple to electroniccircuitry 390 by interconnect 394. In one embodiment, load sensors 410,412, and 414 couple to electronic circuitry 390 by interconnect 392.Measurement module 180 includes at least a power source 494 and a powersource 496. Power source 494 and 496 respectively couple to electroniccircuitry 390 by interconnect 398 and interconnect 396. Interconnect392, 394, 396, and 398 can be flexible interconnect. At least a portionof power source 494 resides within a region defined by the firsttriangle on the medial side of measurement module 180. Similarly, atleast a portion of power source 496 resides within a region of thesecond triangle on the lateral side of measurement module 180. In oneembodiment, measurement module 180 does not compress power source 494 orpower source 496 when under load by the prosthetic knee joint. In oneembodiment, power source 494 and 496 are batteries capable of poweringmeasurement module 180 during a prosthetic joint installation. In oneembodiment, measurement module 180 is disposed of after a prostheticjoint installation and cannot be used again.

Referring briefly to FIGS. 1, 2, 7, 10, 11, 12, 13, 14, 15, and 16measurement module 180 comprises a support structure 340 having exteriormedial surface 182 and exterior lateral surface 184. Exterior medialsurface 182 of support structure 340 has raised regions 350, 352, and354 respectively located at vertexes of a first polygon on exteriormedial surface 182. Exterior lateral surface 184 has raised regions 360,362, and 364 located at vertexes of a second polygon on the exteriorlateral surface 184. In one embodiment, the first polygon differs fromthe second polygon by area, shape, or contour. Peripheral raised region370 on a medial side of support structure 340 couples to raised regions350, 352, and 354. Similarly, peripheral raised region 372 couples toraised regions 360, 362, and 364. In one embodiment, loading applied toa shim coupled to support structure 340 of measurement module 180couples through raised regions 350, 352, and 354 on the medial side andraised regions 360, 362, and 364 on a lateral side. In one embodimentmedial surface 182 and lateral surface 184 is not loaded other thanthrough the raised regions. In one embodiment, peripheral raised regions370 and 372 respectively strengthen raised regions 340, 352, and 354 andraised regions 360, 362, and 364 under load compression. In oneembodiment, raised regions 340, 352, 354, 360, 362, and 364 comprisemore material than the non-raised regions of medial surface 182 andlateral surface 184 of support structure 340.

Measurement module 180 further comprises a support structure 342 havingexterior medial surface 186 and exterior lateral surface 188. Exteriormedial surface 186 of support structure 342 has raised regions 370, 372,and 374 respectively located at vertexes of the first polygon onexterior medial surface 186. Exterior lateral surface 188 of supportstructure 342 has raised regions 380, 382, and 384 located at vertexesof the second polygon on the exterior lateral surface 188. Thus, raisedregions 350, 352, and 354 are respectively aligned to raised regions370, 372, and 374 corresponding to vertexes of the first polygon.Similarly, raised regions 360, 362, and 364 are respectively aligned toraised regions 380, 382, and 384 corresponding to vertexes of the secondpolygon. In one embodiment, loading applied to a shim coupled to supportstructure 342 of measurement module 180 couples through raised regions370, 372, and 374 on the medial side and raised regions 380, 382, and384 on a lateral side. In one embodiment medial surface 186 and lateralsurface 187 is not loaded other than at the raised regions. In oneembodiment, peripheral raised regions 390 and 392 respectivelystrengthen raised regions 370, 372, and 374 and raised regions 380, 382,and 384 under load compression. In one embodiment, raised regions 370,372, 374, 380, 382, and 384 comprise more material than the non-raisedregions of medial surface 186 and lateral surface 188 of supportstructure 342.

Support structures 340 and 342 couple together to form a housing. In oneembodiment, the housing is hermetically sealed. In on embodiment,support structures 340 and 342 can comprise a polymer material, a metal,an alloy, or a composite material. Support structures 340 and 342 can bemolded, machined, formed, or printed. In one embodiment, supportstructure 340 has tongue 426 and support structure 342 has glue channel456. The tongue of support structure 340 fits into the glue channel 456.An adhesive is placed in glue channel 456 to adhere tongue 426 to gluechannel 456 thereby hermetically sealing support structure 340 tosupport structure 342. The housing houses a first plurality of loadsensors and a second plurality of load sensors configured torespectively measure a load applied to a medial side and a lateral sideof measurement module 180. As disclosed herein above, first side 194 ofmeasurement module 180 is configured to couple to a shim of a first typefrom plurality of shims 124. Second side 196 of measurement module 180is configured to couple to a shim of a second from plurality of shims126. The first plurality of load sensors couple between exterior medialsurfaces 182 and 186. In one embodiment, load sensors 400, 402, and 404underlie raised regions 350, 352, and 354 of support structure 342within the housing. Load sensors 400, 402, and 404 respectively couplebetween raised regions 350, 352, and 354 and raised regions 370, 372,and 374 on the medial side of measurement module 180. The secondplurality of load sensors couple between exterior lateral surfaces 184and 188. In one embodiment, load sensors 410, 412, and 414 respectivelyunderlie raised regions 360, 362, and 364 of support structure 342within the housing. Load sensors 410, 412, and 414 respectively couplebetween raised regions 360, 362, and 364 and raised regions 380, 382,and 384 on the lateral side of measurement module 180. Electroniccircuitry couples to sensors 400, 402, 404, 410, 412, and 414 to controla measurement process and transmits measurement data. Computer 110 isconfigured to receive the measurement data and display the measurementdata.

In general, measurement module 180 is a non-symmetric shape. In oneembodiment, measurement module 180 is non-symmetrical about theanterior-posterior (A-P) axis. Exterior medial surface 182 and exteriorlateral surface 184 of support structure 340 can differ in area, shape,or contour. Similarly, exterior medial surface 186 and exterior lateralsurface 188 of support structure 342 can differ in area, shape, orcontour. In one embodiment, the area, shape, and contour of exteriormedial surface 182 of support structure 340 is identical to the area,shape, or contour of exterior medial surface 186 of support structure342. In one embodiment, the area, shape, or contour of exterior lateralsurface 184 of support structure 340 is identical to the area, shape, orcontour of exterior lateral surface 188 of support structure 342. In oneembodiment, each shim of plurality of shims 124 is non-symmetrical aboutthe A-P axis. Similarly, each shim of plurality of shims 126 isnon-symmetrical about the A-P axis.

Electronic circuitry 390 is placed between the medial side and thelateral side of measurement module 180. Electronic circuitry can bemounted and interconnected on a printed circuit board. Electroniccircuitry 390 are not compressed or loaded by the femoral prostheticcomponent. Load sensors 400, 402, and 404 on the medial side ofmeasurement module couple to electronic circuitry 390 by interconnect394. Load sensors 410, 412, and 414 on the lateral side of measurementmodule 180 couple to electronic circuitry by interconnect 392.Interconnect 392 and 394 can have multiple layers of interconnect andcan be flexible. In one embodiment, load sensors 400, 402, and 404 areintegrated into interconnect 394. Similarly, load sensors 410, 412, and414 can be integrated into interconnect 392. Alternatively, the loadsensors can be coupled to interconnect 392 and 394. The load sensors cancomprise MEMs devices, strain gauges, piezo-devices, or capacitors.

Electronic circuitry 390 receives power from power source 494 and powersource 496. Power source 494 and power source 496 are respectivelyplaced on the medial side and the lateral side of measurement module180. A portion of power source 494 couples between the exterior medialsurface 182 and exterior medial surface 186 respectively of supportstructure 340 and support structure 342 of measurement module 180. Aportion of power source 496 couples between exterior lateral surface 184and exterior lateral surface 188 respectively of support structure 340and support structure 342 of measurement module 180. Measurement module180 is configured to not to load power source 494 or power source 496under compression in a prosthetic knee joint.

In one embodiment, a shim can be selected from plurality of shims 124 tocouple to measurement module 180. The plurality of shims 124 are of afirst type and are configured to couple to first side 194 of measurementmodule 180. In one embodiment, the first type corresponds to prostheticcomponents used for a left leg or left knee joint. Shim 140 of pluralityof shims 124 includes medial side columns 244, 242, and 240 and lateralside columns 238, 236, and 234 configured to respectively couple tomedial side raised regions 350, 352, and 354 and lateral side raisedregions 360, 362, and 364. Each shim of plurality of shims 124 differsin height but have the same number of columns on the medial or thelateral sides that couple to the same locations on the first side 194 ofmeasurement module 180. Columns 244, 242, and 240 of shim 140 couple tomedial articular surface 202 of shim 140 at vertexes of the firstpolygon. Columns 238, 236, and 234 couple to lateral articular surface204 of shim 140 at vertexes of the second polygon. In the example thefirst and second polygons are triangles.

In one embodiment, a shim can be selected from plurality of shims 126 tocouple to measurement module 180. The plurality of shims 126 are of asecond type and are configured to couple to second side 196 ofmeasurement module 180. In one embodiment, the second type correspondsto prosthetic components used for a right leg or right knee joint. Shim160 of plurality of shims 126 includes medial side columns 540, 542, and544 and lateral side columns 550, 552, and 554 configured torespectively couple to medial side raised regions 370, 372, and 374 andlateral side raised regions 380, 382, and 384. Each shim of plurality ofshims 126 differs in height but have the same number of columns on themedial or the lateral sides that couple to the same locations on thesecond side 196 of measurement module 180. Columns 380, 382, and 384 ofshim 160 couple to medial articular surface 210 of shim 160 at vertexesof the first polygon. Columns 550, 552, and 554 couple to lateralarticular surface 212 of shim 160 at vertexes of the second polygon.

In one embodiment, first support structure 340 includes medial sideraised regions 420, 422, and 424 and lateral side raised regions 430,432, and 434 respectively on interior medial surface 438 and interiorlateral surface 440. Raised regions 420, 422, and 424 of supportstructure 340 couple to vertexes of the first polygon and align withraised regions 350, 352, and 354. Raised regions 430, 432, and 434 ofsupport structure 340 couple to vertexes of the second polygon and alignwith raised regions 360, 362, and 364. Similarly, second supportstructure 342 includes medial side raise regions 450, 452, and 454 andlateral side raised regions 460, 462, and 464 respectively on interiormedial surface 490 and interior lateral surface 492. Raised regions 450,452, and 454 of support structure 342 couple to vertexes of the firstpolygon and align with raised regions 370, 372, and 374. Raised regions460, 462, and 464 of support structure 342 couple to vertexes of thesecond polygon and align with raised regions 380, 382, and 384. Theinternal raised regions further increase the material located atvertexes of the first or second polygon to strengthen areas receivingloading.

It should be noted that very little data exists on implanted orthopedicdevices. Most of the data is empirically obtained by analyzingorthopedic devices that have been used in a human subject or simulateduse. Wear patterns, material issues, and failure mechanisms are studied.Although, information can be garnered through this type of study it doesyield substantive data about the initial installation, post-operativeuse, and long term use from a measurement perspective. Just as eachperson is different, each device installation is different havingvariations in initial loading, balance, and alignment. Having measureddata and using the data to install an orthopedic device will greatlyincrease the consistency of the implant procedure thereby reducingrework and maximizing the life of the device. In at least one exemplaryembodiment, the measured data can be collected to a database where itcan be stored and analyzed. For example, once a relevant sample of themeasured data is collected, it can be used to define optimal initialmeasured settings, geometries, and alignments for maximizing the lifeand usability of an implanted orthopedic device.

The present invention is applicable to a wide range of medical andnonmedical applications including, but not limited to, frequencycompensation; control of, or alarms for, physical systems; or monitoringor measuring physical parameters of interest. The level of accuracy andrepeatability attainable in a highly compact sensing module or devicemay be applicable to many medical applications monitoring or measuringphysiological parameters throughout the human body including, notlimited to, bone density, movement, viscosity, and pressure of variousfluids, localized temperature, etc. with applications in the vascular,lymph, respiratory, digestive system, muscles, bones, and joints, othersoft tissue areas, and interstitial fluids.

While the present invention has been described with reference toparticular embodiments, those skilled in the art will recognize thatmany changes may be made thereto without departing from the spirit andscope of the present invention. Each of these embodiments and obviousvariations thereof is contemplated as falling within the spirit andscope of the invention.

What is claimed is:
 1. A prosthetic knee component system comprising: ameasurement module having a first side and a second side configured tocouple to (i) a first shim on the first side and (ii) a second shim onthe second side; the first shim, wherein the first shim has a firstmedial articular surface and a first lateral articular surface, whereina first plurality of columns of the first shim are configured to coupleto the first medial articular surface and a second plurality of columnsof the first shim are configured to couple to the first lateralarticular surface; and the second shim, wherein the second shim has asecond medial articular surface and a second lateral articular surface,wherein a third plurality of columns of the second shim are configuredto couple to the second medial articular surface and a fourth pluralityof columns of the second shim are configured to couple to the secondlateral articular surface; wherein the measurement module is configuredto measure loading applied to at least one of the first shim and thesecond shim; and wherein the measurement module comprises: a firstmedial surface on the first side of the measurement module, a firstlateral surface on the first side of the measurement module, a firstload sensor, a second load sensor; a first raised portion protrudingoutwardly from the first medial surface, wherein the first raisedportion is aligned with the first load sensor and configured to alignwith a column of the first plurality of columns of the first shim; and asecond raised portion protruding outwardly from the first lateralsurface, wherein the second raised portion is aligned with the secondload sensor and configured to align with a column of the secondplurality of columns of the first shim.
 2. The prosthetic knee componentsystem of claim 1, wherein the first shim and the second shim arenon-symmetrical.
 3. The prosthetic knee component system of claim 1,wherein the first medial articular surface differs in area or contourfrom the first lateral articular surface of the first shim; and whereinthe second medial articular surface differs in area or contour from thesecond lateral articular surface.
 4. The prosthetic knee componentsystem of claim 1, wherein the first shim includes a first structuralwebbing coupling a first sidewall of the first shim to the firstplurality of columns of the first shim or the second plurality ofcolumns of the first shim; and wherein the second shim includes a secondstructural webbing coupling a second sidewall of the second shim to thethird plurality of columns of the second shim or the fourth plurality ofcolumns of the second shim.
 5. The prosthetic knee component system ofclaim 4, wherein the first structural webbing extends between aplurality of columns of the first plurality of columns of the firstshim, and wherein the first structural webbing extends between aplurality of columns of the second plurality of columns of the firstshim; or wherein the second structural webbing extends between aplurality of columns of the third plurality of columns of the secondshim, and wherein the second structural webbing couples between aplurality of columns of the fourth plurality of columns of the secondshim.
 6. The prosthetic knee component system of claim 1, furtherincluding a third shim and a fourth shim, wherein the third shim has adifferent height from the first shim and the fourth shim has a differentheight from the second shim.
 7. The prosthetic knee component system ofclaim 1, wherein the measurement module further includes a postextending outward from a first side surface; wherein the first shimincludes a first slot; wherein the second shim includes a second slot;wherein the post extends outward in a direction transverse to (i) afirst direction in which the first side faces and (ii) a seconddirection in which the second side faces; and wherein the post isconfigured to be inserted into at least one of: the first slot to couplethe measurement module to the first shim, and the second slot to couplethe measurement module to the second shim.
 8. The prosthetic kneecomponent system of claim 1, wherein the measurement module furthercomprises: a third load sensor, a fourth load sensor; a third raisedportion protruding outwardly from the first medial surface, wherein thethird raised portion is aligned with the third load sensor; and a fourthraised portion protruding outwardly from the first lateral surface,wherein the fourth raised portion is aligned with the fourth loadsensor.
 9. The prosthetic knee component system of claim 8, wherein themeasurement module further comprises a peripheral raised regionprotruding outwardly from the first medial surface and extending alongan edge of the first medial surface, wherein the peripheral raisedregion extends from the first raised portion to the third raisedportion.
 10. The prosthetic knee component system of claim 1, whereinthe measurement module further comprises a second medial surface on thesecond side of the measurement module, a second lateral surface on thesecond side of the measurement module, a third raised portion protrudingoutwardly from the second medial surface, wherein the third raisedportion is aligned with the first load sensor; and a fourth raisedportion protruding outwardly from the second lateral surface, whereinthe fourth raised portion is aligned with the second load sensor;wherein each of the first medial surface and the first lateral surfaceis on the first side of the measurement module, and each of the secondmedial surface and the second lateral surface is on the second side ofthe measurement module.
 11. A prosthetic knee component systemcomprising: a first shim having a first medial articular surface and afirst lateral articular surface, wherein each of a first plurality ofcolumns is coupled to the first medial articular surface and each of asecond plurality of columns is coupled to the first lateral articularsurface, and wherein the first medial articular surface differs in areaor contour from the first lateral articular surface; a second shimhaving a second medial articular surface and a second lateral articularsurface, wherein each of a third Plurality of columns is coupled to thesecond medial articular surface and each of a fourth Plurality ofcolumns is coupled to the second lateral articular surface, wherein thesecond medial articular surface differs in area or contour from thesecond lateral articular surface, and wherein the second shim isdifferent from the first shim; a measurement module having a first sidemedial surface, a first side lateral surface, a first load sensorconfigured to measure load applied to the first side medial surface, anda second load sensor configured to measure load applied to the firstside lateral surface, wherein each of the first side medial surface andthe first side lateral surface is on a first side of the measurementmodule; wherein each column of the first plurality of columns isconfigured to align with a corresponding raised portion of the firstside medial surface, and each column of the second plurality of columnsis configured to align with a corresponding raised portion of the firstside lateral surface; wherein a first raised portion of thecorresponding raised portions of the first side medial surface projectsoutwardly from the first side medial surface and is aligned with thefirst load sensor, and a second raised portion of the correspondingraised portions of the first side lateral surface projects outwardlyfrom the first side lateral surface and is aligned with the second loadsensor; wherein each of the third plurality of columns is configured tocouple to a second side medial surface of the measurement module andeach of the fourth Plurality of columns is configured to couple to asecond side lateral surface of the measurement module, and wherein themeasurement module is configured to measure loading applied to thesecond medial articular surface and the second lateral articular surfaceof the second shim.
 12. The prosthetic knee component system of claim11, wherein the measurement module is configured to measure loadingapplied to the first medial articular surface and the first lateralarticular surface of the first shim.
 13. The prosthetic knee componentsystem of claim 12, wherein the first load sensor of the measurementmodule is configured to underlie a column of the first plurality ofcolumns of the first shim, and wherein the first load sensor is acapacitor, a piezo-resistive load sensor, or a MEMs load sensor.
 14. Aprosthetic knee component system comprising: a first shim, wherein thefirst shim configured for use with one of (i) a left knee and (ii) aright knee, the first shim having a first medial articular surface and afirst lateral articular surface, wherein each of a first column, asecond column, and a third column is coupled to the first medialarticular surface, and each of a fourth column, a fifth column, and asixth column is coupled to the first lateral articular surface, andwherein the first medial articular surface on the first shim differs inarea or contour from the first lateral articular surface on the firstshim; a measurement module having a first medial surface, a firstlateral surface, a second medial surface, and a second lateral surface,wherein each of the first medial surface and the first lateral surfaceis on a first side of the measurement module and each of the secondmedial surface and the second lateral surface is on a second side of themeasurement module; wherein the first shim is configured to couple tothe first side of the measurement module; wherein the measurement moduleis configured to couple to a second shim at the second side of themeasurement module, wherein the second shim is different from the firstshim; wherein the first medial surface includes a first raised portion,a second raised portion, and a third raised portion that each protrudeoutward from the first medial surface, wherein the first lateral surfaceincludes a fourth raised portion, a fifth raised portion, and a sixthraised portion that each protrude outward from the first lateralsurface; wherein the first column is configured to align with the firstraised portion, the second column is configured to align with the secondraised portion, the third column is configured to align with the thirdraised portion, the fourth column is configured to align with the fourthraised portion, the fifth column is configured to align with the fifthraised portion, and the sixth column is configured to align with thesixth raised portion; wherein the second medial surface has a seventhraised portion, an eighth raised portion, and a ninth raised portionthat each protrude outward from the second medial surface; and whereinthe measurement module is configured to measure load applied to at leastone of the first shim and the second shim.
 15. The prosthetic kneecomponent system of claim 14, further including the second shim having asecond medial articular surface and a second lateral articular surface;wherein each of a seventh column, an eighth column, and a ninth columnis coupled to the second medial articular surface of the second shim;wherein each of a tenth column, an eleventh column, and a twelfth columnis coupled to the second lateral articular surface of the second shim;wherein the second medial articular surface differs in area or contourfrom the second lateral articular surface; wherein the second lateralsurface has a tenth raised portion, an eleventh raised portion, and atwelfth raised portion that each protrude outward from the secondlateral surface; and wherein the seventh column is configured to alignwith the seventh raised portion, the eighth column is configured toalign with the eighth raised portion, the ninth column is configured toalign with the ninth raised portion, the tenth column is configured toalign with the tenth raised portion, the eleventh column is configuredto align with the eleventh raised portion, and the twelfth column isconfigured to align with the twelfth raised portion.
 16. The prostheticknee component system of claim 15, wherein the measurement moduleincludes a first load sensor, a second load sensor, a third load sensor,a fourth load sensor, a fifth load sensor, and a sixth load sensor,wherein the first load sensor is configured to underlie the firstcolumn, the second load sensor is configured to underlie the secondcolumn, and the third load sensor is configured to underlie the thirdcolumn, and wherein the fourth load sensor is configured to underlie thefourth column, the fifth load sensor is configured to underlie the fifthcolumn, and the sixth load sensor is configured to underlie the sixthcolumn.
 17. The prosthetic knee component system of claim 15, whereinthe measurement module is configured to measure loading applied to thesecond medial articular surface and the second lateral articular surfaceof the second shim, wherein the measurement module includes (i) a firstload sensor configured to underlie the seventh column, (ii) a secondload sensor configured to underlie the eighth column, and (iii) a thirdload sensor configured to underlie the ninth column.
 18. The prostheticknee component system of claim 15, wherein the first medial surface onthe first side of the measurement module differs in area or contour fromthe first lateral surface on the first side of the measurement module.